Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Colin McCabe]

On Wed, May 2, 2018, at 14:54, John Roesler wrote:
> Thanks Jason,
> 
> I did find some production use cases "on the internet" that use poll(0)
> *just* to join the group initially and ignore the response. I suppose the
> assumption is that it'll be empty on the very first call to poll with
> timeout=0. In my opinion, this usage is unsafe, since there's a declared
> return value. I proposed the method to give these use cases a safe
> alternative.
> 
> Of course, there's another safe alternative: just don't ignore the response.
> 
> I'd agree with the decision to just deprecate the old poll(long) and add
> only a new poll(Duration). It should be obvious that there's no
> non-deprecated way to do what the code I found is doing, so those
> developers will either alter their code to handle the response or they will
> come back and ask us for the awaitAssignmentMetadata method.
> 
> Better to present a simpler api and wait for a reason to make it more
> complicated.
> 
> I'm fine with suggestions 1,2, and 3. Unless Richard objects super fast,
> I'll update the KIP momentarily.
> 
> Regarding the ClientTimeoutException, this was introduced earlier in this
> discussion when Becket pointed out that the TimeoutException is a subclass
> of ApiException, and therefore implies that a call to the broker timed out.

Hmm.  AdminClient uses TimeoutException for timeouts that don't occur on the 
broker.  For example, if we fail to get cluster metadata within the given 
request timeout, the request gets a TimeoutException.

BrokerNotAvailableException is another ApiException that is thrown on the 
client side rather than the broker side.  For example, if you attempt to call 
alterReplicaLogDirs and specify a broker that can't be found in the cluster 
metadata, AdminClient will fail with BrokerNotAvailableException.  This 
exception does not come from the broker (there is no broker to talk to, in this 
case).

In general, I interpret ApiExceptions to be exceptions that users should be 
able to handle when calling a Kafka API.
I don't think they always have to come from a broker.

Colin

> 
> Reconsidering this point, I found the javadoc on ApiException to be a
> little ambiguous. All it says is that "any API exception that is part of
> the public protocol should be a subclass of this class...". It's not clear
> to me whether this is the broker's API/protocol or more generally *any*
> API/protocol. So we'd have to bring the lawyers in, but I think we can just
> say it's the latter and keep the old exception.
> 
> I'm not sure if it's an important distiction to users whether their request
> timed out as a broker side timeout, an HTTP timeout, or a client-side
> timeout. In any case, they'd want to retry for a while and then fail if
> they can't get their request through.
> 
> Plus RetryableException also inherits from ApiException, and that one is
> ubiquitous. Adding a new exception would require users to catch both
> RetriableException and ClientTimeoutException, which seems odd since the
> latter is retriable.
> 
> All in all, I'm now in favor of sticking with the current TimeoutException.
> If there's some higher-level problem with the ApiException being used this
> way, I think it should be addressed holistically in a separate KIP.
> 
> So, I'll go ahead and switch the KIP back to TimeoutException, unless
> Becket wants to argue (harder) in favor of the ClientTimeoutException.
> 
> Thanks,
> -John
> 
> 
> On Wed, May 2, 2018 at 3:55 PM, Jason Gustafson  wrote:
> 
> > I think John's proposal look reasonable to me. My only doubt is about use
> > cases for the new `awaitAssignmentMetadata` API. I think the basic idea is
> > that we want a way to block until we have joined the consumer group, but we
> > do not want to await fetched data. Maybe another way to accomplish this
> > would be to add a `PollOptions` argument which specified the condition we
> > are awaiting? It's a little weird that we'd have two separate APIs where
> > the group membership can change. I know this functionality can be helpful
> > in testing, but we should probably spend some more time understanding and
> > motivating the general use cases.
> >
> > Since we're leaving around the old poll() with its current behavior for
> > now, I wonder if we could leave this as potential future work?
> >
> > Other than that, I have a few minor suggestions and I'm happy with the KIP:
> >
> > 1. Can we use Duration across the board for all of these APIs?
> > 2. Can we cover the following blocking APIs with in this KIP:
> > `partitionsFor`, `listTopics`, `offsetsForTimes`, `beginningOffsets`,
> > `endOffsets`?
> > 3. Perhaps we can add a `close(Duration)` and deprecate the one accepting
> > `TimeUnit`?
> > 4. Seems we don't really need `ClientTimeoutException` since we already
> > have `TimeoutException`?
> >
> > Thanks,
> > Jason
> >
> >
> >
> > On Wed, Apr 25, 2018 at 2:14 PM, Guozhang Wang  wrote:
> >
> > > Previously there 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[John Roesler]

Hey Richard,

I've updated the KIP with the changes discussed here. If you're happy with
the state of it, I think that we're probably ready to call for a vote.

However, I'm about to take a week off for vacation. Do you mind sending the
[VOTE] message and managing the vote thread?

Obviously, you can count me as a non-binding +1.

Thanks,
-John

On Wed, May 2, 2018 at 8:08 PM, Jason Gustafson  wrote:

> Hey John,
>
> Yeah, I appreciate Becket's point. We do tend to abuse the initial intent
> of ApiException. It's just that it can be awkward to come up with another
> name when the ApiException already has a reasonable and appropriate name
> for the user API. `ClientTimeoutException` is a perfect example of this
> awkwardness. In practice I don't think the convention has provided much
> benefit. I looked around the code and saw only a handful of cases where we
> were checking ApiException directly, and it was just to determine the log
> level of a message. I think I'd probably take the more concise name, even
> if it's a slight abuse of the convention. We use it in similar scenarios in
> the producer, for what it's worth.
>
> -Jason
>
>
> On Wed, May 2, 2018 at 3:26 PM, Richard Yu 
> wrote:
>
> > Hi John,
> >
> > I don't have any objections to this KIP change. Please go ahead.
> >
> > Thanks,
> > Richard
> >
> > On Wed, May 2, 2018 at 2:54 PM, John Roesler  wrote:
> >
> > > Thanks Jason,
> > >
> > > I did find some production use cases "on the internet" that use poll(0)
> > > *just* to join the group initially and ignore the response. I suppose
> the
> > > assumption is that it'll be empty on the very first call to poll with
> > > timeout=0. In my opinion, this usage is unsafe, since there's a
> declared
> > > return value. I proposed the method to give these use cases a safe
> > > alternative.
> > >
> > > Of course, there's another safe alternative: just don't ignore the
> > > response.
> > >
> > > I'd agree with the decision to just deprecate the old poll(long) and
> add
> > > only a new poll(Duration). It should be obvious that there's no
> > > non-deprecated way to do what the code I found is doing, so those
> > > developers will either alter their code to handle the response or they
> > will
> > > come back and ask us for the awaitAssignmentMetadata method.
> > >
> > > Better to present a simpler api and wait for a reason to make it more
> > > complicated.
> > >
> > > I'm fine with suggestions 1,2, and 3. Unless Richard objects super
> fast,
> > > I'll update the KIP momentarily.
> > >
> > > Regarding the ClientTimeoutException, this was introduced earlier in
> this
> > > discussion when Becket pointed out that the TimeoutException is a
> > subclass
> > > of ApiException, and therefore implies that a call to the broker timed
> > out.
> > >
> > > Reconsidering this point, I found the javadoc on ApiException to be a
> > > little ambiguous. All it says is that "any API exception that is part
> of
> > > the public protocol should be a subclass of this class...". It's not
> > clear
> > > to me whether this is the broker's API/protocol or more generally *any*
> > > API/protocol. So we'd have to bring the lawyers in, but I think we can
> > just
> > > say it's the latter and keep the old exception.
> > >
> > > I'm not sure if it's an important distiction to users whether their
> > request
> > > timed out as a broker side timeout, an HTTP timeout, or a client-side
> > > timeout. In any case, they'd want to retry for a while and then fail if
> > > they can't get their request through.
> > >
> > > Plus RetryableException also inherits from ApiException, and that one
> is
> > > ubiquitous. Adding a new exception would require users to catch both
> > > RetriableException and ClientTimeoutException, which seems odd since
> the
> > > latter is retriable.
> > >
> > > All in all, I'm now in favor of sticking with the current
> > TimeoutException.
> > > If there's some higher-level problem with the ApiException being used
> > this
> > > way, I think it should be addressed holistically in a separate KIP.
> > >
> > > So, I'll go ahead and switch the KIP back to TimeoutException, unless
> > > Becket wants to argue (harder) in favor of the ClientTimeoutException.
> > >
> > > Thanks,
> > > -John
> > >
> > >
> > > On Wed, May 2, 2018 at 3:55 PM, Jason Gustafson 
> > > wrote:
> > >
> > > > I think John's proposal look reasonable to me. My only doubt is about
> > use
> > > > cases for the new `awaitAssignmentMetadata` API. I think the basic
> idea
> > > is
> > > > that we want a way to block until we have joined the consumer group,
> > but
> > > we
> > > > do not want to await fetched data. Maybe another way to accomplish
> this
> > > > would be to add a `PollOptions` argument which specified the
> condition
> > we
> > > > are awaiting? It's a little weird that we'd have two separate APIs
> > where
> > > > the group membership can change. I 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Jason Gustafson]

Hey John,

Yeah, I appreciate Becket's point. We do tend to abuse the initial intent
of ApiException. It's just that it can be awkward to come up with another
name when the ApiException already has a reasonable and appropriate name
for the user API. `ClientTimeoutException` is a perfect example of this
awkwardness. In practice I don't think the convention has provided much
benefit. I looked around the code and saw only a handful of cases where we
were checking ApiException directly, and it was just to determine the log
level of a message. I think I'd probably take the more concise name, even
if it's a slight abuse of the convention. We use it in similar scenarios in
the producer, for what it's worth.

-Jason


On Wed, May 2, 2018 at 3:26 PM, Richard Yu 
wrote:

> Hi John,
>
> I don't have any objections to this KIP change. Please go ahead.
>
> Thanks,
> Richard
>
> On Wed, May 2, 2018 at 2:54 PM, John Roesler  wrote:
>
> > Thanks Jason,
> >
> > I did find some production use cases "on the internet" that use poll(0)
> > *just* to join the group initially and ignore the response. I suppose the
> > assumption is that it'll be empty on the very first call to poll with
> > timeout=0. In my opinion, this usage is unsafe, since there's a declared
> > return value. I proposed the method to give these use cases a safe
> > alternative.
> >
> > Of course, there's another safe alternative: just don't ignore the
> > response.
> >
> > I'd agree with the decision to just deprecate the old poll(long) and add
> > only a new poll(Duration). It should be obvious that there's no
> > non-deprecated way to do what the code I found is doing, so those
> > developers will either alter their code to handle the response or they
> will
> > come back and ask us for the awaitAssignmentMetadata method.
> >
> > Better to present a simpler api and wait for a reason to make it more
> > complicated.
> >
> > I'm fine with suggestions 1,2, and 3. Unless Richard objects super fast,
> > I'll update the KIP momentarily.
> >
> > Regarding the ClientTimeoutException, this was introduced earlier in this
> > discussion when Becket pointed out that the TimeoutException is a
> subclass
> > of ApiException, and therefore implies that a call to the broker timed
> out.
> >
> > Reconsidering this point, I found the javadoc on ApiException to be a
> > little ambiguous. All it says is that "any API exception that is part of
> > the public protocol should be a subclass of this class...". It's not
> clear
> > to me whether this is the broker's API/protocol or more generally *any*
> > API/protocol. So we'd have to bring the lawyers in, but I think we can
> just
> > say it's the latter and keep the old exception.
> >
> > I'm not sure if it's an important distiction to users whether their
> request
> > timed out as a broker side timeout, an HTTP timeout, or a client-side
> > timeout. In any case, they'd want to retry for a while and then fail if
> > they can't get their request through.
> >
> > Plus RetryableException also inherits from ApiException, and that one is
> > ubiquitous. Adding a new exception would require users to catch both
> > RetriableException and ClientTimeoutException, which seems odd since the
> > latter is retriable.
> >
> > All in all, I'm now in favor of sticking with the current
> TimeoutException.
> > If there's some higher-level problem with the ApiException being used
> this
> > way, I think it should be addressed holistically in a separate KIP.
> >
> > So, I'll go ahead and switch the KIP back to TimeoutException, unless
> > Becket wants to argue (harder) in favor of the ClientTimeoutException.
> >
> > Thanks,
> > -John
> >
> >
> > On Wed, May 2, 2018 at 3:55 PM, Jason Gustafson 
> > wrote:
> >
> > > I think John's proposal look reasonable to me. My only doubt is about
> use
> > > cases for the new `awaitAssignmentMetadata` API. I think the basic idea
> > is
> > > that we want a way to block until we have joined the consumer group,
> but
> > we
> > > do not want to await fetched data. Maybe another way to accomplish this
> > > would be to add a `PollOptions` argument which specified the condition
> we
> > > are awaiting? It's a little weird that we'd have two separate APIs
> where
> > > the group membership can change. I know this functionality can be
> helpful
> > > in testing, but we should probably spend some more time understanding
> and
> > > motivating the general use cases.
> > >
> > > Since we're leaving around the old poll() with its current behavior for
> > > now, I wonder if we could leave this as potential future work?
> > >
> > > Other than that, I have a few minor suggestions and I'm happy with the
> > KIP:
> > >
> > > 1. Can we use Duration across the board for all of these APIs?
> > > 2. Can we cover the following blocking APIs with in this KIP:
> > > `partitionsFor`, `listTopics`, `offsetsForTimes`, `beginningOffsets`,
> > > `endOffsets`?
> > > 3. 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Hi John,

I don't have any objections to this KIP change. Please go ahead.

Thanks,
Richard

On Wed, May 2, 2018 at 2:54 PM, John Roesler  wrote:

> Thanks Jason,
>
> I did find some production use cases "on the internet" that use poll(0)
> *just* to join the group initially and ignore the response. I suppose the
> assumption is that it'll be empty on the very first call to poll with
> timeout=0. In my opinion, this usage is unsafe, since there's a declared
> return value. I proposed the method to give these use cases a safe
> alternative.
>
> Of course, there's another safe alternative: just don't ignore the
> response.
>
> I'd agree with the decision to just deprecate the old poll(long) and add
> only a new poll(Duration). It should be obvious that there's no
> non-deprecated way to do what the code I found is doing, so those
> developers will either alter their code to handle the response or they will
> come back and ask us for the awaitAssignmentMetadata method.
>
> Better to present a simpler api and wait for a reason to make it more
> complicated.
>
> I'm fine with suggestions 1,2, and 3. Unless Richard objects super fast,
> I'll update the KIP momentarily.
>
> Regarding the ClientTimeoutException, this was introduced earlier in this
> discussion when Becket pointed out that the TimeoutException is a subclass
> of ApiException, and therefore implies that a call to the broker timed out.
>
> Reconsidering this point, I found the javadoc on ApiException to be a
> little ambiguous. All it says is that "any API exception that is part of
> the public protocol should be a subclass of this class...". It's not clear
> to me whether this is the broker's API/protocol or more generally *any*
> API/protocol. So we'd have to bring the lawyers in, but I think we can just
> say it's the latter and keep the old exception.
>
> I'm not sure if it's an important distiction to users whether their request
> timed out as a broker side timeout, an HTTP timeout, or a client-side
> timeout. In any case, they'd want to retry for a while and then fail if
> they can't get their request through.
>
> Plus RetryableException also inherits from ApiException, and that one is
> ubiquitous. Adding a new exception would require users to catch both
> RetriableException and ClientTimeoutException, which seems odd since the
> latter is retriable.
>
> All in all, I'm now in favor of sticking with the current TimeoutException.
> If there's some higher-level problem with the ApiException being used this
> way, I think it should be addressed holistically in a separate KIP.
>
> So, I'll go ahead and switch the KIP back to TimeoutException, unless
> Becket wants to argue (harder) in favor of the ClientTimeoutException.
>
> Thanks,
> -John
>
>
> On Wed, May 2, 2018 at 3:55 PM, Jason Gustafson 
> wrote:
>
> > I think John's proposal look reasonable to me. My only doubt is about use
> > cases for the new `awaitAssignmentMetadata` API. I think the basic idea
> is
> > that we want a way to block until we have joined the consumer group, but
> we
> > do not want to await fetched data. Maybe another way to accomplish this
> > would be to add a `PollOptions` argument which specified the condition we
> > are awaiting? It's a little weird that we'd have two separate APIs where
> > the group membership can change. I know this functionality can be helpful
> > in testing, but we should probably spend some more time understanding and
> > motivating the general use cases.
> >
> > Since we're leaving around the old poll() with its current behavior for
> > now, I wonder if we could leave this as potential future work?
> >
> > Other than that, I have a few minor suggestions and I'm happy with the
> KIP:
> >
> > 1. Can we use Duration across the board for all of these APIs?
> > 2. Can we cover the following blocking APIs with in this KIP:
> > `partitionsFor`, `listTopics`, `offsetsForTimes`, `beginningOffsets`,
> > `endOffsets`?
> > 3. Perhaps we can add a `close(Duration)` and deprecate the one accepting
> > `TimeUnit`?
> > 4. Seems we don't really need `ClientTimeoutException` since we already
> > have `TimeoutException`?
> >
> > Thanks,
> > Jason
> >
> >
> >
> > On Wed, Apr 25, 2018 at 2:14 PM, Guozhang Wang 
> wrote:
> >
> > > Previously there are some debates on whether we should add this
> > nonblocking
> > > behavior via a config v.s. via overloaded functions. To make progress
> on
> > > this discussion we need to first figure that part out. I'm in favor of
> > the
> > > current approach of overloaded functions over the config since if we
> are
> > > going to have multiple configs other than a single one to control
> timeout
> > > semantics it may be even confusing: take our producer side configs for
> an
> > > example, right now we have "request.timeout.ms" and "max.block.ms" and
> > we
> > > are proposing to add another one in KIP-91. But I'd also like to hear
> > from
> > > people who's in favor 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[John Roesler]

Thanks Jason,

I did find some production use cases "on the internet" that use poll(0)
*just* to join the group initially and ignore the response. I suppose the
assumption is that it'll be empty on the very first call to poll with
timeout=0. In my opinion, this usage is unsafe, since there's a declared
return value. I proposed the method to give these use cases a safe
alternative.

Of course, there's another safe alternative: just don't ignore the response.

I'd agree with the decision to just deprecate the old poll(long) and add
only a new poll(Duration). It should be obvious that there's no
non-deprecated way to do what the code I found is doing, so those
developers will either alter their code to handle the response or they will
come back and ask us for the awaitAssignmentMetadata method.

Better to present a simpler api and wait for a reason to make it more
complicated.

I'm fine with suggestions 1,2, and 3. Unless Richard objects super fast,
I'll update the KIP momentarily.

Regarding the ClientTimeoutException, this was introduced earlier in this
discussion when Becket pointed out that the TimeoutException is a subclass
of ApiException, and therefore implies that a call to the broker timed out.

Reconsidering this point, I found the javadoc on ApiException to be a
little ambiguous. All it says is that "any API exception that is part of
the public protocol should be a subclass of this class...". It's not clear
to me whether this is the broker's API/protocol or more generally *any*
API/protocol. So we'd have to bring the lawyers in, but I think we can just
say it's the latter and keep the old exception.

I'm not sure if it's an important distiction to users whether their request
timed out as a broker side timeout, an HTTP timeout, or a client-side
timeout. In any case, they'd want to retry for a while and then fail if
they can't get their request through.

Plus RetryableException also inherits from ApiException, and that one is
ubiquitous. Adding a new exception would require users to catch both
RetriableException and ClientTimeoutException, which seems odd since the
latter is retriable.

All in all, I'm now in favor of sticking with the current TimeoutException.
If there's some higher-level problem with the ApiException being used this
way, I think it should be addressed holistically in a separate KIP.

So, I'll go ahead and switch the KIP back to TimeoutException, unless
Becket wants to argue (harder) in favor of the ClientTimeoutException.

Thanks,
-John


On Wed, May 2, 2018 at 3:55 PM, Jason Gustafson  wrote:

> I think John's proposal look reasonable to me. My only doubt is about use
> cases for the new `awaitAssignmentMetadata` API. I think the basic idea is
> that we want a way to block until we have joined the consumer group, but we
> do not want to await fetched data. Maybe another way to accomplish this
> would be to add a `PollOptions` argument which specified the condition we
> are awaiting? It's a little weird that we'd have two separate APIs where
> the group membership can change. I know this functionality can be helpful
> in testing, but we should probably spend some more time understanding and
> motivating the general use cases.
>
> Since we're leaving around the old poll() with its current behavior for
> now, I wonder if we could leave this as potential future work?
>
> Other than that, I have a few minor suggestions and I'm happy with the KIP:
>
> 1. Can we use Duration across the board for all of these APIs?
> 2. Can we cover the following blocking APIs with in this KIP:
> `partitionsFor`, `listTopics`, `offsetsForTimes`, `beginningOffsets`,
> `endOffsets`?
> 3. Perhaps we can add a `close(Duration)` and deprecate the one accepting
> `TimeUnit`?
> 4. Seems we don't really need `ClientTimeoutException` since we already
> have `TimeoutException`?
>
> Thanks,
> Jason
>
>
>
> On Wed, Apr 25, 2018 at 2:14 PM, Guozhang Wang  wrote:
>
> > Previously there are some debates on whether we should add this
> nonblocking
> > behavior via a config v.s. via overloaded functions. To make progress on
> > this discussion we need to first figure that part out. I'm in favor of
> the
> > current approach of overloaded functions over the config since if we are
> > going to have multiple configs other than a single one to control timeout
> > semantics it may be even confusing: take our producer side configs for an
> > example, right now we have "request.timeout.ms" and "max.block.ms" and
> we
> > are proposing to add another one in KIP-91. But I'd also like to hear
> from
> > people who's in favor of the configs.
> >
> >
> > Guozhang
> >
> >
> > On Wed, Apr 25, 2018 at 1:39 PM, John Roesler  wrote:
> >
> > > Re Ted's last comment, that style of async API requires some thread to
> > > actually drive the request/response cycle and invoke the callback when
> > it's
> > > complete. Right now, this happens in the caller's thread as a
> side-effect
> 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Jason Gustafson]

I think John's proposal look reasonable to me. My only doubt is about use
cases for the new `awaitAssignmentMetadata` API. I think the basic idea is
that we want a way to block until we have joined the consumer group, but we
do not want to await fetched data. Maybe another way to accomplish this
would be to add a `PollOptions` argument which specified the condition we
are awaiting? It's a little weird that we'd have two separate APIs where
the group membership can change. I know this functionality can be helpful
in testing, but we should probably spend some more time understanding and
motivating the general use cases.

Since we're leaving around the old poll() with its current behavior for
now, I wonder if we could leave this as potential future work?

Other than that, I have a few minor suggestions and I'm happy with the KIP:

1. Can we use Duration across the board for all of these APIs?
2. Can we cover the following blocking APIs with in this KIP:
`partitionsFor`, `listTopics`, `offsetsForTimes`, `beginningOffsets`,
`endOffsets`?
3. Perhaps we can add a `close(Duration)` and deprecate the one accepting
`TimeUnit`?
4. Seems we don't really need `ClientTimeoutException` since we already
have `TimeoutException`?

Thanks,
Jason



On Wed, Apr 25, 2018 at 2:14 PM, Guozhang Wang  wrote:

> Previously there are some debates on whether we should add this nonblocking
> behavior via a config v.s. via overloaded functions. To make progress on
> this discussion we need to first figure that part out. I'm in favor of the
> current approach of overloaded functions over the config since if we are
> going to have multiple configs other than a single one to control timeout
> semantics it may be even confusing: take our producer side configs for an
> example, right now we have "request.timeout.ms" and "max.block.ms" and we
> are proposing to add another one in KIP-91. But I'd also like to hear from
> people who's in favor of the configs.
>
>
> Guozhang
>
>
> On Wed, Apr 25, 2018 at 1:39 PM, John Roesler  wrote:
>
> > Re Ted's last comment, that style of async API requires some thread to
> > actually drive the request/response cycle and invoke the callback when
> it's
> > complete. Right now, this happens in the caller's thread as a side-effect
> > of calling poll(). But that clearly won't work for poll() itself!
> >
> > In the future, I think we'd like to add a background thread to drive the
> > request/response loops, and then make all these methods return
> > Future.
> >
> > But we don't need to bite that off right now.
> >
> > The "async" model I'm proposing is really just a generalization of the
> one
> > that poll already partially implements: when you call poll, it fires off
> > any requests it needs to make and checks if any responses are ready. If
> so,
> > it returns them. If not, it returns empty. When you call poll() again, it
> > again checks on the responses from last time, and so forth.
> >
> > But that model currently only applies to the "fetch" part of poll. I'm
> > proposing that we extend it to the "metadata update" part of poll as
> well.
> >
> > However, as previously discussed, doing this in place would break the
> > semantics of poll that folks currently rely on, so I propose to add new
> > methods and deprecate the existing poll method. Here's what I'm thinking:
> > https://github.com/apache/kafka/pull/4855 . In the discussion on that
> PR,
> > I've described in greater detail how the async+blocking semantics work.
> >
> > I'll update KIP-266 with this interface for poll().
> >
> > It would be great to get this discussion moving again so we can get these
> > changes into 2.0. What does everyone think about this?
> >
> > Thanks,
> > -John
> >
> > On Thu, Apr 19, 2018 at 5:12 PM, John Roesler  wrote:
> >
> > > Thanks for the tip, Ted!
> > >
> > > On Thu, Apr 19, 2018 at 12:12 PM, Ted Yu  wrote:
> > >
> > >> John:
> > >> In case you want to pursue async poll, it seems (by looking at current
> > >> API)
> > >> that introducing PollCallback follows existing pattern(s).
> > >>
> > >> e.g. KafkaConsumer#commitAsync(OffsetCommitCallback)
> > >>
> > >> FYI
> > >>
> > >> On Thu, Apr 19, 2018 at 10:08 AM, John Roesler 
> > wrote:
> > >>
> > >> > Hi Richard,
> > >> >
> > >> > Thanks for the invitation! I do think it would be safer to
> introduce a
> > >> new
> > >> > poll
> > >> > method than to change the semantics of the old one. I've been
> mulling
> > >> about
> > >> > whether the new one could still have (slightly different) async
> > >> semantics
> > >> > with
> > >> > a timeout of 0. If possible, I'd like to avoid introducing another
> new
> > >> > "asyncPoll".
> > >> >
> > >> > I'm planning to run some experiments and dig into the
> implementation a
> > >> bit
> > >> > more before solidifying the proposal. I'll update the KIP as you
> > >> suggest at
> > >> > that point,
> > >> > and then can call for 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Guozhang Wang]

Previously there are some debates on whether we should add this nonblocking
behavior via a config v.s. via overloaded functions. To make progress on
this discussion we need to first figure that part out. I'm in favor of the
current approach of overloaded functions over the config since if we are
going to have multiple configs other than a single one to control timeout
semantics it may be even confusing: take our producer side configs for an
example, right now we have "request.timeout.ms" and "max.block.ms" and we
are proposing to add another one in KIP-91. But I'd also like to hear from
people who's in favor of the configs.


Guozhang


On Wed, Apr 25, 2018 at 1:39 PM, John Roesler  wrote:

> Re Ted's last comment, that style of async API requires some thread to
> actually drive the request/response cycle and invoke the callback when it's
> complete. Right now, this happens in the caller's thread as a side-effect
> of calling poll(). But that clearly won't work for poll() itself!
>
> In the future, I think we'd like to add a background thread to drive the
> request/response loops, and then make all these methods return
> Future.
>
> But we don't need to bite that off right now.
>
> The "async" model I'm proposing is really just a generalization of the one
> that poll already partially implements: when you call poll, it fires off
> any requests it needs to make and checks if any responses are ready. If so,
> it returns them. If not, it returns empty. When you call poll() again, it
> again checks on the responses from last time, and so forth.
>
> But that model currently only applies to the "fetch" part of poll. I'm
> proposing that we extend it to the "metadata update" part of poll as well.
>
> However, as previously discussed, doing this in place would break the
> semantics of poll that folks currently rely on, so I propose to add new
> methods and deprecate the existing poll method. Here's what I'm thinking:
> https://github.com/apache/kafka/pull/4855 . In the discussion on that PR,
> I've described in greater detail how the async+blocking semantics work.
>
> I'll update KIP-266 with this interface for poll().
>
> It would be great to get this discussion moving again so we can get these
> changes into 2.0. What does everyone think about this?
>
> Thanks,
> -John
>
> On Thu, Apr 19, 2018 at 5:12 PM, John Roesler  wrote:
>
> > Thanks for the tip, Ted!
> >
> > On Thu, Apr 19, 2018 at 12:12 PM, Ted Yu  wrote:
> >
> >> John:
> >> In case you want to pursue async poll, it seems (by looking at current
> >> API)
> >> that introducing PollCallback follows existing pattern(s).
> >>
> >> e.g. KafkaConsumer#commitAsync(OffsetCommitCallback)
> >>
> >> FYI
> >>
> >> On Thu, Apr 19, 2018 at 10:08 AM, John Roesler 
> wrote:
> >>
> >> > Hi Richard,
> >> >
> >> > Thanks for the invitation! I do think it would be safer to introduce a
> >> new
> >> > poll
> >> > method than to change the semantics of the old one. I've been mulling
> >> about
> >> > whether the new one could still have (slightly different) async
> >> semantics
> >> > with
> >> > a timeout of 0. If possible, I'd like to avoid introducing another new
> >> > "asyncPoll".
> >> >
> >> > I'm planning to run some experiments and dig into the implementation a
> >> bit
> >> > more before solidifying the proposal. I'll update the KIP as you
> >> suggest at
> >> > that point,
> >> > and then can call for another round of reviews and voting.
> >> >
> >> > Thanks,
> >> > -John
> >> >
> >> > On Tue, Apr 17, 2018 at 4:53 PM, Richard Yu <
> yohan.richard...@gmail.com
> >> >
> >> > wrote:
> >> >
> >> > > Hi John,
> >> > >
> >> > > Do you have a preference for fixing the poll() method (e.g. using
> >> > asyncPoll
> >> > > or just sticking with the current method but with an extra timeout
> >> > > parameter) ? I think your current proposition for KIP-288 is better
> >> than
> >> > > what I have on my side. If you think there is something that you
> want
> >> to
> >> > > add, you could go ahead and change KIP-266 to your liking. Just to
> >> note
> >> > > that it would be preferable that if one of us modifies this KIP, it
> >> would
> >> > > be best to mention your change on this thread to let each other know
> >> > (makes
> >> > > it easier to coordinate progress).
> >> > >
> >> > > Thanks,
> >> > > Richard
> >> > >
> >> > > On Tue, Apr 17, 2018 at 2:07 PM, John Roesler 
> >> wrote:
> >> > >
> >> > > > Ok, I'll close the discussion on KIP-288 and mark it discarded.
> >> > > >
> >> > > > We can solidify the design for poll in KIP-266, and once it's
> >> approved,
> >> > > > I'll coordinate with Qiang Zhao on the PR for the poll part of the
> >> > work.
> >> > > > Once that is merged, you'll have a clean slate for the rest of the
> >> > work.
> >> > > >
> >> > > > On Tue, Apr 17, 2018 at 3:39 PM, Richard Yu <
> >> > yohan.richard...@gmail.com>
> >> > > > wrote:
> >> > > >
> >> > > > 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[John Roesler]

Hi Richard,

I've updated the KIP with my proposed replacement methods for the poll use
cases.

Since I'm no longer proposing to alter poll(long) in place, I don't think
it's necessary to ever through a ClientTimeoutException from
poll(Duration). The new method, awaitAssignmentMetadata, however would
throw ClientTimeoutException.

This KIP will take effect in 2.0 at the earliest (KIP freeze for 2.0 is 22
May 2018). We are dropping JDK7 in 2.0, which means we can now consider
using JDK8 APIs. In that light, I recommend that in all our new variants,
we accept a single java.time.Duration instead of a (long, TimeUnit) pair. I
have included this API in my update to the poll parts of KIP-266.

This might be a nitpick, but I've chosen to name the parameters in my new
poll and awaitAssignmentMetadata "maxBlockTime" instead of "timeout", since
in the implementation I've proposed, it's not actually a timeout. Rather,
it's just the amount of time we block for operations to complete. If this
time runs out, we can call the method again and it'll just pick up waiting
instead of trying again from scratch. I think this same thinking applies to
the other methods you're considering adding.

Thanks,
John



On Wed, Apr 25, 2018 at 3:39 PM, John Roesler  wrote:

> Re Ted's last comment, that style of async API requires some thread to
> actually drive the request/response cycle and invoke the callback when it's
> complete. Right now, this happens in the caller's thread as a side-effect
> of calling poll(). But that clearly won't work for poll() itself!
>
> In the future, I think we'd like to add a background thread to drive the
> request/response loops, and then make all these methods return
> Future.
>
> But we don't need to bite that off right now.
>
> The "async" model I'm proposing is really just a generalization of the one
> that poll already partially implements: when you call poll, it fires off
> any requests it needs to make and checks if any responses are ready. If so,
> it returns them. If not, it returns empty. When you call poll() again, it
> again checks on the responses from last time, and so forth.
>
> But that model currently only applies to the "fetch" part of poll. I'm
> proposing that we extend it to the "metadata update" part of poll as well.
>
> However, as previously discussed, doing this in place would break the
> semantics of poll that folks currently rely on, so I propose to add new
> methods and deprecate the existing poll method. Here's what I'm thinking:
> https://github.com/apache/kafka/pull/4855 . In the discussion on that PR,
> I've described in greater detail how the async+blocking semantics work.
>
> I'll update KIP-266 with this interface for poll().
>
> It would be great to get this discussion moving again so we can get these
> changes into 2.0. What does everyone think about this?
>
> Thanks,
> -John
>
> On Thu, Apr 19, 2018 at 5:12 PM, John Roesler  wrote:
>
>> Thanks for the tip, Ted!
>>
>> On Thu, Apr 19, 2018 at 12:12 PM, Ted Yu  wrote:
>>
>>> John:
>>> In case you want to pursue async poll, it seems (by looking at current
>>> API)
>>> that introducing PollCallback follows existing pattern(s).
>>>
>>> e.g. KafkaConsumer#commitAsync(OffsetCommitCallback)
>>>
>>> FYI
>>>
>>> On Thu, Apr 19, 2018 at 10:08 AM, John Roesler 
>>> wrote:
>>>
>>> > Hi Richard,
>>> >
>>> > Thanks for the invitation! I do think it would be safer to introduce a
>>> new
>>> > poll
>>> > method than to change the semantics of the old one. I've been mulling
>>> about
>>> > whether the new one could still have (slightly different) async
>>> semantics
>>> > with
>>> > a timeout of 0. If possible, I'd like to avoid introducing another new
>>> > "asyncPoll".
>>> >
>>> > I'm planning to run some experiments and dig into the implementation a
>>> bit
>>> > more before solidifying the proposal. I'll update the KIP as you
>>> suggest at
>>> > that point,
>>> > and then can call for another round of reviews and voting.
>>> >
>>> > Thanks,
>>> > -John
>>> >
>>> > On Tue, Apr 17, 2018 at 4:53 PM, Richard Yu <
>>> yohan.richard...@gmail.com>
>>> > wrote:
>>> >
>>> > > Hi John,
>>> > >
>>> > > Do you have a preference for fixing the poll() method (e.g. using
>>> > asyncPoll
>>> > > or just sticking with the current method but with an extra timeout
>>> > > parameter) ? I think your current proposition for KIP-288 is better
>>> than
>>> > > what I have on my side. If you think there is something that you
>>> want to
>>> > > add, you could go ahead and change KIP-266 to your liking. Just to
>>> note
>>> > > that it would be preferable that if one of us modifies this KIP, it
>>> would
>>> > > be best to mention your change on this thread to let each other know
>>> > (makes
>>> > > it easier to coordinate progress).
>>> > >
>>> > > Thanks,
>>> > > Richard
>>> > >
>>> > > On Tue, Apr 17, 2018 at 2:07 PM, John Roesler 
>>> wrote:
>>> > >
>>> 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[John Roesler]

Re Ted's last comment, that style of async API requires some thread to
actually drive the request/response cycle and invoke the callback when it's
complete. Right now, this happens in the caller's thread as a side-effect
of calling poll(). But that clearly won't work for poll() itself!

In the future, I think we'd like to add a background thread to drive the
request/response loops, and then make all these methods return
Future.

But we don't need to bite that off right now.

The "async" model I'm proposing is really just a generalization of the one
that poll already partially implements: when you call poll, it fires off
any requests it needs to make and checks if any responses are ready. If so,
it returns them. If not, it returns empty. When you call poll() again, it
again checks on the responses from last time, and so forth.

But that model currently only applies to the "fetch" part of poll. I'm
proposing that we extend it to the "metadata update" part of poll as well.

However, as previously discussed, doing this in place would break the
semantics of poll that folks currently rely on, so I propose to add new
methods and deprecate the existing poll method. Here's what I'm thinking:
https://github.com/apache/kafka/pull/4855 . In the discussion on that PR,
I've described in greater detail how the async+blocking semantics work.

I'll update KIP-266 with this interface for poll().

It would be great to get this discussion moving again so we can get these
changes into 2.0. What does everyone think about this?

Thanks,
-John

On Thu, Apr 19, 2018 at 5:12 PM, John Roesler  wrote:

> Thanks for the tip, Ted!
>
> On Thu, Apr 19, 2018 at 12:12 PM, Ted Yu  wrote:
>
>> John:
>> In case you want to pursue async poll, it seems (by looking at current
>> API)
>> that introducing PollCallback follows existing pattern(s).
>>
>> e.g. KafkaConsumer#commitAsync(OffsetCommitCallback)
>>
>> FYI
>>
>> On Thu, Apr 19, 2018 at 10:08 AM, John Roesler  wrote:
>>
>> > Hi Richard,
>> >
>> > Thanks for the invitation! I do think it would be safer to introduce a
>> new
>> > poll
>> > method than to change the semantics of the old one. I've been mulling
>> about
>> > whether the new one could still have (slightly different) async
>> semantics
>> > with
>> > a timeout of 0. If possible, I'd like to avoid introducing another new
>> > "asyncPoll".
>> >
>> > I'm planning to run some experiments and dig into the implementation a
>> bit
>> > more before solidifying the proposal. I'll update the KIP as you
>> suggest at
>> > that point,
>> > and then can call for another round of reviews and voting.
>> >
>> > Thanks,
>> > -John
>> >
>> > On Tue, Apr 17, 2018 at 4:53 PM, Richard Yu > >
>> > wrote:
>> >
>> > > Hi John,
>> > >
>> > > Do you have a preference for fixing the poll() method (e.g. using
>> > asyncPoll
>> > > or just sticking with the current method but with an extra timeout
>> > > parameter) ? I think your current proposition for KIP-288 is better
>> than
>> > > what I have on my side. If you think there is something that you want
>> to
>> > > add, you could go ahead and change KIP-266 to your liking. Just to
>> note
>> > > that it would be preferable that if one of us modifies this KIP, it
>> would
>> > > be best to mention your change on this thread to let each other know
>> > (makes
>> > > it easier to coordinate progress).
>> > >
>> > > Thanks,
>> > > Richard
>> > >
>> > > On Tue, Apr 17, 2018 at 2:07 PM, John Roesler 
>> wrote:
>> > >
>> > > > Ok, I'll close the discussion on KIP-288 and mark it discarded.
>> > > >
>> > > > We can solidify the design for poll in KIP-266, and once it's
>> approved,
>> > > > I'll coordinate with Qiang Zhao on the PR for the poll part of the
>> > work.
>> > > > Once that is merged, you'll have a clean slate for the rest of the
>> > work.
>> > > >
>> > > > On Tue, Apr 17, 2018 at 3:39 PM, Richard Yu <
>> > yohan.richard...@gmail.com>
>> > > > wrote:
>> > > >
>> > > > > Hi John,
>> > > > >
>> > > > > I think that you could finish your PR that corresponds with
>> KIP-288
>> > and
>> > > > > merge it. I can finish my side of the work afterwards.
>> > > > >
>> > > > > On another note, adding an asynchronized version of poll() would
>> make
>> > > > > sense, particularily since the current version of Kafka does not
>> > > support
>> > > > > it.
>> > > > >
>> > > > > Thanks
>> > > > > Richar
>> > > > >
>> > > > > On Tue, Apr 17, 2018 at 12:30 PM, John Roesler > >
>> > > > wrote:
>> > > > >
>> > > > > > Cross-pollinating from some discussion we've had on KIP-288,
>> > > > > >
>> > > > > > I think there's a good reason that poll() takes a timeout when
>> none
>> > > of
>> > > > > the
>> > > > > > other methods do, and it's relevant to this discussion. The
>> timeout
>> > > in
>> > > > > > poll() is effectively implementing a long-poll API (on the
>> client
>> > > side,
>> > > > > so

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[John Roesler]

Thanks for the tip, Ted!

On Thu, Apr 19, 2018 at 12:12 PM, Ted Yu  wrote:

> John:
> In case you want to pursue async poll, it seems (by looking at current API)
> that introducing PollCallback follows existing pattern(s).
>
> e.g. KafkaConsumer#commitAsync(OffsetCommitCallback)
>
> FYI
>
> On Thu, Apr 19, 2018 at 10:08 AM, John Roesler  wrote:
>
> > Hi Richard,
> >
> > Thanks for the invitation! I do think it would be safer to introduce a
> new
> > poll
> > method than to change the semantics of the old one. I've been mulling
> about
> > whether the new one could still have (slightly different) async semantics
> > with
> > a timeout of 0. If possible, I'd like to avoid introducing another new
> > "asyncPoll".
> >
> > I'm planning to run some experiments and dig into the implementation a
> bit
> > more before solidifying the proposal. I'll update the KIP as you suggest
> at
> > that point,
> > and then can call for another round of reviews and voting.
> >
> > Thanks,
> > -John
> >
> > On Tue, Apr 17, 2018 at 4:53 PM, Richard Yu 
> > wrote:
> >
> > > Hi John,
> > >
> > > Do you have a preference for fixing the poll() method (e.g. using
> > asyncPoll
> > > or just sticking with the current method but with an extra timeout
> > > parameter) ? I think your current proposition for KIP-288 is better
> than
> > > what I have on my side. If you think there is something that you want
> to
> > > add, you could go ahead and change KIP-266 to your liking. Just to note
> > > that it would be preferable that if one of us modifies this KIP, it
> would
> > > be best to mention your change on this thread to let each other know
> > (makes
> > > it easier to coordinate progress).
> > >
> > > Thanks,
> > > Richard
> > >
> > > On Tue, Apr 17, 2018 at 2:07 PM, John Roesler 
> wrote:
> > >
> > > > Ok, I'll close the discussion on KIP-288 and mark it discarded.
> > > >
> > > > We can solidify the design for poll in KIP-266, and once it's
> approved,
> > > > I'll coordinate with Qiang Zhao on the PR for the poll part of the
> > work.
> > > > Once that is merged, you'll have a clean slate for the rest of the
> > work.
> > > >
> > > > On Tue, Apr 17, 2018 at 3:39 PM, Richard Yu <
> > yohan.richard...@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi John,
> > > > >
> > > > > I think that you could finish your PR that corresponds with KIP-288
> > and
> > > > > merge it. I can finish my side of the work afterwards.
> > > > >
> > > > > On another note, adding an asynchronized version of poll() would
> make
> > > > > sense, particularily since the current version of Kafka does not
> > > support
> > > > > it.
> > > > >
> > > > > Thanks
> > > > > Richar
> > > > >
> > > > > On Tue, Apr 17, 2018 at 12:30 PM, John Roesler 
> > > > wrote:
> > > > >
> > > > > > Cross-pollinating from some discussion we've had on KIP-288,
> > > > > >
> > > > > > I think there's a good reason that poll() takes a timeout when
> none
> > > of
> > > > > the
> > > > > > other methods do, and it's relevant to this discussion. The
> timeout
> > > in
> > > > > > poll() is effectively implementing a long-poll API (on the client
> > > side,
> > > > > so
> > > > > > it's not really long-poll, but the programmer-facing behavior is
> > the
> > > > > same).
> > > > > > The timeout isn't really bounding the execution time of the
> method,
> > > but
> > > > > > instead giving a max time that callers are willing to wait around
> > and
> > > > see
> > > > > > if any results show up.
> > > > > >
> > > > > > If I understand the code sufficiently, it would be perfectly
> > > reasonable
> > > > > for
> > > > > > a caller to use a timeout of 0 to implement async poll, it would
> > just
> > > > > mean
> > > > > > that KafkaConsumer would just check on each call if there's a
> > > response
> > > > > > ready and if not, fire off a new request without waiting for a
> > > > response.
> > > > > >
> > > > > > As such, it seems inappropriate to throw a ClientTimeoutException
> > > from
> > > > > > poll(), except possibly if the initial phase of ensuring an
> > > assignment
> > > > > > times out. We wouldn't want the method contract to be "returns a
> > > > > non-empty
> > > > > > collection or throws a ClientTimeoutException"
> > > > > >
> > > > > > Now, I'm wondering if we should actually consider one of my
> > rejected
> > > > > > alternatives, to treat the "operation timeout" as a separate
> > > parameter
> > > > > from
> > > > > > the "long-poll time". Or maybe adding an "asyncPoll(timeout, time
> > > > unit)"
> > > > > > that only uses the timeout to bound metadata updates and
> otherwise
> > > > > behaves
> > > > > > like the current "poll(0)".
> > > > > >
> > > > > > Thanks,
> > > > > > -John
> > > > > >
> > > > > > On Tue, Apr 17, 2018 at 2:05 PM, John Roesler  >
> > > > wrote:
> > > > > >
> > > > > > > Hey Richard,
> > > > > > >
> > > > > > > As you noticed, the 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Ted Yu]

John:
In case you want to pursue async poll, it seems (by looking at current API)
that introducing PollCallback follows existing pattern(s).

e.g. KafkaConsumer#commitAsync(OffsetCommitCallback)

FYI

On Thu, Apr 19, 2018 at 10:08 AM, John Roesler  wrote:

> Hi Richard,
>
> Thanks for the invitation! I do think it would be safer to introduce a new
> poll
> method than to change the semantics of the old one. I've been mulling about
> whether the new one could still have (slightly different) async semantics
> with
> a timeout of 0. If possible, I'd like to avoid introducing another new
> "asyncPoll".
>
> I'm planning to run some experiments and dig into the implementation a bit
> more before solidifying the proposal. I'll update the KIP as you suggest at
> that point,
> and then can call for another round of reviews and voting.
>
> Thanks,
> -John
>
> On Tue, Apr 17, 2018 at 4:53 PM, Richard Yu 
> wrote:
>
> > Hi John,
> >
> > Do you have a preference for fixing the poll() method (e.g. using
> asyncPoll
> > or just sticking with the current method but with an extra timeout
> > parameter) ? I think your current proposition for KIP-288 is better than
> > what I have on my side. If you think there is something that you want to
> > add, you could go ahead and change KIP-266 to your liking. Just to note
> > that it would be preferable that if one of us modifies this KIP, it would
> > be best to mention your change on this thread to let each other know
> (makes
> > it easier to coordinate progress).
> >
> > Thanks,
> > Richard
> >
> > On Tue, Apr 17, 2018 at 2:07 PM, John Roesler  wrote:
> >
> > > Ok, I'll close the discussion on KIP-288 and mark it discarded.
> > >
> > > We can solidify the design for poll in KIP-266, and once it's approved,
> > > I'll coordinate with Qiang Zhao on the PR for the poll part of the
> work.
> > > Once that is merged, you'll have a clean slate for the rest of the
> work.
> > >
> > > On Tue, Apr 17, 2018 at 3:39 PM, Richard Yu <
> yohan.richard...@gmail.com>
> > > wrote:
> > >
> > > > Hi John,
> > > >
> > > > I think that you could finish your PR that corresponds with KIP-288
> and
> > > > merge it. I can finish my side of the work afterwards.
> > > >
> > > > On another note, adding an asynchronized version of poll() would make
> > > > sense, particularily since the current version of Kafka does not
> > support
> > > > it.
> > > >
> > > > Thanks
> > > > Richar
> > > >
> > > > On Tue, Apr 17, 2018 at 12:30 PM, John Roesler 
> > > wrote:
> > > >
> > > > > Cross-pollinating from some discussion we've had on KIP-288,
> > > > >
> > > > > I think there's a good reason that poll() takes a timeout when none
> > of
> > > > the
> > > > > other methods do, and it's relevant to this discussion. The timeout
> > in
> > > > > poll() is effectively implementing a long-poll API (on the client
> > side,
> > > > so
> > > > > it's not really long-poll, but the programmer-facing behavior is
> the
> > > > same).
> > > > > The timeout isn't really bounding the execution time of the method,
> > but
> > > > > instead giving a max time that callers are willing to wait around
> and
> > > see
> > > > > if any results show up.
> > > > >
> > > > > If I understand the code sufficiently, it would be perfectly
> > reasonable
> > > > for
> > > > > a caller to use a timeout of 0 to implement async poll, it would
> just
> > > > mean
> > > > > that KafkaConsumer would just check on each call if there's a
> > response
> > > > > ready and if not, fire off a new request without waiting for a
> > > response.
> > > > >
> > > > > As such, it seems inappropriate to throw a ClientTimeoutException
> > from
> > > > > poll(), except possibly if the initial phase of ensuring an
> > assignment
> > > > > times out. We wouldn't want the method contract to be "returns a
> > > > non-empty
> > > > > collection or throws a ClientTimeoutException"
> > > > >
> > > > > Now, I'm wondering if we should actually consider one of my
> rejected
> > > > > alternatives, to treat the "operation timeout" as a separate
> > parameter
> > > > from
> > > > > the "long-poll time". Or maybe adding an "asyncPoll(timeout, time
> > > unit)"
> > > > > that only uses the timeout to bound metadata updates and otherwise
> > > > behaves
> > > > > like the current "poll(0)".
> > > > >
> > > > > Thanks,
> > > > > -John
> > > > >
> > > > > On Tue, Apr 17, 2018 at 2:05 PM, John Roesler 
> > > wrote:
> > > > >
> > > > > > Hey Richard,
> > > > > >
> > > > > > As you noticed, the newly introduced KIP-288 overlaps with this
> > one.
> > > > > Sorry
> > > > > > for stepping on your toes... How would you like to proceed? I'm
> > happy
> > > > to
> > > > > > "close" KIP-288 in deference to this KIP.
> > > > > >
> > > > > > With respect to poll(), reading this discussion gave me a new
> idea
> > > for
> > > > > > providing a non-breaking update path... What if we introduce a

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[John Roesler]

Hi Richard,

Thanks for the invitation! I do think it would be safer to introduce a new
poll
method than to change the semantics of the old one. I've been mulling about
whether the new one could still have (slightly different) async semantics
with
a timeout of 0. If possible, I'd like to avoid introducing another new
"asyncPoll".

I'm planning to run some experiments and dig into the implementation a bit
more before solidifying the proposal. I'll update the KIP as you suggest at
that point,
and then can call for another round of reviews and voting.

Thanks,
-John

On Tue, Apr 17, 2018 at 4:53 PM, Richard Yu 
wrote:

> Hi John,
>
> Do you have a preference for fixing the poll() method (e.g. using asyncPoll
> or just sticking with the current method but with an extra timeout
> parameter) ? I think your current proposition for KIP-288 is better than
> what I have on my side. If you think there is something that you want to
> add, you could go ahead and change KIP-266 to your liking. Just to note
> that it would be preferable that if one of us modifies this KIP, it would
> be best to mention your change on this thread to let each other know (makes
> it easier to coordinate progress).
>
> Thanks,
> Richard
>
> On Tue, Apr 17, 2018 at 2:07 PM, John Roesler  wrote:
>
> > Ok, I'll close the discussion on KIP-288 and mark it discarded.
> >
> > We can solidify the design for poll in KIP-266, and once it's approved,
> > I'll coordinate with Qiang Zhao on the PR for the poll part of the work.
> > Once that is merged, you'll have a clean slate for the rest of the work.
> >
> > On Tue, Apr 17, 2018 at 3:39 PM, Richard Yu 
> > wrote:
> >
> > > Hi John,
> > >
> > > I think that you could finish your PR that corresponds with KIP-288 and
> > > merge it. I can finish my side of the work afterwards.
> > >
> > > On another note, adding an asynchronized version of poll() would make
> > > sense, particularily since the current version of Kafka does not
> support
> > > it.
> > >
> > > Thanks
> > > Richar
> > >
> > > On Tue, Apr 17, 2018 at 12:30 PM, John Roesler 
> > wrote:
> > >
> > > > Cross-pollinating from some discussion we've had on KIP-288,
> > > >
> > > > I think there's a good reason that poll() takes a timeout when none
> of
> > > the
> > > > other methods do, and it's relevant to this discussion. The timeout
> in
> > > > poll() is effectively implementing a long-poll API (on the client
> side,
> > > so
> > > > it's not really long-poll, but the programmer-facing behavior is the
> > > same).
> > > > The timeout isn't really bounding the execution time of the method,
> but
> > > > instead giving a max time that callers are willing to wait around and
> > see
> > > > if any results show up.
> > > >
> > > > If I understand the code sufficiently, it would be perfectly
> reasonable
> > > for
> > > > a caller to use a timeout of 0 to implement async poll, it would just
> > > mean
> > > > that KafkaConsumer would just check on each call if there's a
> response
> > > > ready and if not, fire off a new request without waiting for a
> > response.
> > > >
> > > > As such, it seems inappropriate to throw a ClientTimeoutException
> from
> > > > poll(), except possibly if the initial phase of ensuring an
> assignment
> > > > times out. We wouldn't want the method contract to be "returns a
> > > non-empty
> > > > collection or throws a ClientTimeoutException"
> > > >
> > > > Now, I'm wondering if we should actually consider one of my rejected
> > > > alternatives, to treat the "operation timeout" as a separate
> parameter
> > > from
> > > > the "long-poll time". Or maybe adding an "asyncPoll(timeout, time
> > unit)"
> > > > that only uses the timeout to bound metadata updates and otherwise
> > > behaves
> > > > like the current "poll(0)".
> > > >
> > > > Thanks,
> > > > -John
> > > >
> > > > On Tue, Apr 17, 2018 at 2:05 PM, John Roesler 
> > wrote:
> > > >
> > > > > Hey Richard,
> > > > >
> > > > > As you noticed, the newly introduced KIP-288 overlaps with this
> one.
> > > > Sorry
> > > > > for stepping on your toes... How would you like to proceed? I'm
> happy
> > > to
> > > > > "close" KIP-288 in deference to this KIP.
> > > > >
> > > > > With respect to poll(), reading this discussion gave me a new idea
> > for
> > > > > providing a non-breaking update path... What if we introduce a new
> > > > variant
> > > > > 'poll(long timeout, TimeUnit unit)' that displays the new, desired
> > > > > behavior, and just leave the old method alone?
> > > > >
> > > > > Thanks,
> > > > > -John
> > > > >
> > > > > On Tue, Apr 17, 2018 at 12:09 PM, Richard Yu <
> > > yohan.richard...@gmail.com
> > > > >
> > > > > wrote:
> > > > >
> > > > >> Hi all,
> > > > >>
> > > > >> If possible, would a committer please review?
> > > > >>
> > > > >> Thanks
> > > > >>
> > > > >> On Sun, Apr 1, 2018 at 7:24 PM, Richard Yu <
> > > 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Hi John,

Do you have a preference for fixing the poll() method (e.g. using asyncPoll
or just sticking with the current method but with an extra timeout
parameter) ? I think your current proposition for KIP-288 is better than
what I have on my side. If you think there is something that you want to
add, you could go ahead and change KIP-266 to your liking. Just to note
that it would be preferable that if one of us modifies this KIP, it would
be best to mention your change on this thread to let each other know (makes
it easier to coordinate progress).

Thanks,
Richard

On Tue, Apr 17, 2018 at 2:07 PM, John Roesler  wrote:

> Ok, I'll close the discussion on KIP-288 and mark it discarded.
>
> We can solidify the design for poll in KIP-266, and once it's approved,
> I'll coordinate with Qiang Zhao on the PR for the poll part of the work.
> Once that is merged, you'll have a clean slate for the rest of the work.
>
> On Tue, Apr 17, 2018 at 3:39 PM, Richard Yu 
> wrote:
>
> > Hi John,
> >
> > I think that you could finish your PR that corresponds with KIP-288 and
> > merge it. I can finish my side of the work afterwards.
> >
> > On another note, adding an asynchronized version of poll() would make
> > sense, particularily since the current version of Kafka does not support
> > it.
> >
> > Thanks
> > Richar
> >
> > On Tue, Apr 17, 2018 at 12:30 PM, John Roesler 
> wrote:
> >
> > > Cross-pollinating from some discussion we've had on KIP-288,
> > >
> > > I think there's a good reason that poll() takes a timeout when none of
> > the
> > > other methods do, and it's relevant to this discussion. The timeout in
> > > poll() is effectively implementing a long-poll API (on the client side,
> > so
> > > it's not really long-poll, but the programmer-facing behavior is the
> > same).
> > > The timeout isn't really bounding the execution time of the method, but
> > > instead giving a max time that callers are willing to wait around and
> see
> > > if any results show up.
> > >
> > > If I understand the code sufficiently, it would be perfectly reasonable
> > for
> > > a caller to use a timeout of 0 to implement async poll, it would just
> > mean
> > > that KafkaConsumer would just check on each call if there's a response
> > > ready and if not, fire off a new request without waiting for a
> response.
> > >
> > > As such, it seems inappropriate to throw a ClientTimeoutException from
> > > poll(), except possibly if the initial phase of ensuring an assignment
> > > times out. We wouldn't want the method contract to be "returns a
> > non-empty
> > > collection or throws a ClientTimeoutException"
> > >
> > > Now, I'm wondering if we should actually consider one of my rejected
> > > alternatives, to treat the "operation timeout" as a separate parameter
> > from
> > > the "long-poll time". Or maybe adding an "asyncPoll(timeout, time
> unit)"
> > > that only uses the timeout to bound metadata updates and otherwise
> > behaves
> > > like the current "poll(0)".
> > >
> > > Thanks,
> > > -John
> > >
> > > On Tue, Apr 17, 2018 at 2:05 PM, John Roesler 
> wrote:
> > >
> > > > Hey Richard,
> > > >
> > > > As you noticed, the newly introduced KIP-288 overlaps with this one.
> > > Sorry
> > > > for stepping on your toes... How would you like to proceed? I'm happy
> > to
> > > > "close" KIP-288 in deference to this KIP.
> > > >
> > > > With respect to poll(), reading this discussion gave me a new idea
> for
> > > > providing a non-breaking update path... What if we introduce a new
> > > variant
> > > > 'poll(long timeout, TimeUnit unit)' that displays the new, desired
> > > > behavior, and just leave the old method alone?
> > > >
> > > > Thanks,
> > > > -John
> > > >
> > > > On Tue, Apr 17, 2018 at 12:09 PM, Richard Yu <
> > yohan.richard...@gmail.com
> > > >
> > > > wrote:
> > > >
> > > >> Hi all,
> > > >>
> > > >> If possible, would a committer please review?
> > > >>
> > > >> Thanks
> > > >>
> > > >> On Sun, Apr 1, 2018 at 7:24 PM, Richard Yu <
> > yohan.richard...@gmail.com>
> > > >> wrote:
> > > >>
> > > >> > Hi Guozhang,
> > > >> >
> > > >> > I have clarified the KIP a bit to account for Becket's suggestion
> on
> > > >> > ClientTimeoutException.
> > > >> > About adding an extra config, you were right about my intentions.
> I
> > am
> > > >> > just wondering if the config
> > > >> > should be included, since Ismael seems to favor an extra
> > > configuration,
> > > >> >
> > > >> > Thanks,
> > > >> > Richard
> > > >> >
> > > >> > On Sun, Apr 1, 2018 at 5:35 PM, Guozhang Wang  >
> > > >> wrote:
> > > >> >
> > > >> >> Hi Richard,
> > > >> >>
> > > >> >> Regarding the streams side changes, we plan to incorporate with
> the
> > > new
> > > >> >> APIs once the KIP is done, which is only internal code changes
> and
> > > >> hence
> > > >> >> do
> > > >> >> not need to include in the KIP.
> > > >> >>
> > > >> >> Could you update the KIP 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[John Roesler]

Ok, I'll close the discussion on KIP-288 and mark it discarded.

We can solidify the design for poll in KIP-266, and once it's approved,
I'll coordinate with Qiang Zhao on the PR for the poll part of the work.
Once that is merged, you'll have a clean slate for the rest of the work.

On Tue, Apr 17, 2018 at 3:39 PM, Richard Yu 
wrote:

> Hi John,
>
> I think that you could finish your PR that corresponds with KIP-288 and
> merge it. I can finish my side of the work afterwards.
>
> On another note, adding an asynchronized version of poll() would make
> sense, particularily since the current version of Kafka does not support
> it.
>
> Thanks
> Richar
>
> On Tue, Apr 17, 2018 at 12:30 PM, John Roesler  wrote:
>
> > Cross-pollinating from some discussion we've had on KIP-288,
> >
> > I think there's a good reason that poll() takes a timeout when none of
> the
> > other methods do, and it's relevant to this discussion. The timeout in
> > poll() is effectively implementing a long-poll API (on the client side,
> so
> > it's not really long-poll, but the programmer-facing behavior is the
> same).
> > The timeout isn't really bounding the execution time of the method, but
> > instead giving a max time that callers are willing to wait around and see
> > if any results show up.
> >
> > If I understand the code sufficiently, it would be perfectly reasonable
> for
> > a caller to use a timeout of 0 to implement async poll, it would just
> mean
> > that KafkaConsumer would just check on each call if there's a response
> > ready and if not, fire off a new request without waiting for a response.
> >
> > As such, it seems inappropriate to throw a ClientTimeoutException from
> > poll(), except possibly if the initial phase of ensuring an assignment
> > times out. We wouldn't want the method contract to be "returns a
> non-empty
> > collection or throws a ClientTimeoutException"
> >
> > Now, I'm wondering if we should actually consider one of my rejected
> > alternatives, to treat the "operation timeout" as a separate parameter
> from
> > the "long-poll time". Or maybe adding an "asyncPoll(timeout, time unit)"
> > that only uses the timeout to bound metadata updates and otherwise
> behaves
> > like the current "poll(0)".
> >
> > Thanks,
> > -John
> >
> > On Tue, Apr 17, 2018 at 2:05 PM, John Roesler  wrote:
> >
> > > Hey Richard,
> > >
> > > As you noticed, the newly introduced KIP-288 overlaps with this one.
> > Sorry
> > > for stepping on your toes... How would you like to proceed? I'm happy
> to
> > > "close" KIP-288 in deference to this KIP.
> > >
> > > With respect to poll(), reading this discussion gave me a new idea for
> > > providing a non-breaking update path... What if we introduce a new
> > variant
> > > 'poll(long timeout, TimeUnit unit)' that displays the new, desired
> > > behavior, and just leave the old method alone?
> > >
> > > Thanks,
> > > -John
> > >
> > > On Tue, Apr 17, 2018 at 12:09 PM, Richard Yu <
> yohan.richard...@gmail.com
> > >
> > > wrote:
> > >
> > >> Hi all,
> > >>
> > >> If possible, would a committer please review?
> > >>
> > >> Thanks
> > >>
> > >> On Sun, Apr 1, 2018 at 7:24 PM, Richard Yu <
> yohan.richard...@gmail.com>
> > >> wrote:
> > >>
> > >> > Hi Guozhang,
> > >> >
> > >> > I have clarified the KIP a bit to account for Becket's suggestion on
> > >> > ClientTimeoutException.
> > >> > About adding an extra config, you were right about my intentions. I
> am
> > >> > just wondering if the config
> > >> > should be included, since Ismael seems to favor an extra
> > configuration,
> > >> >
> > >> > Thanks,
> > >> > Richard
> > >> >
> > >> > On Sun, Apr 1, 2018 at 5:35 PM, Guozhang Wang 
> > >> wrote:
> > >> >
> > >> >> Hi Richard,
> > >> >>
> > >> >> Regarding the streams side changes, we plan to incorporate with the
> > new
> > >> >> APIs once the KIP is done, which is only internal code changes and
> > >> hence
> > >> >> do
> > >> >> not need to include in the KIP.
> > >> >>
> > >> >> Could you update the KIP because it has been quite obsoleted from
> the
> > >> >> discussed topics, and I'm a bit loosing track on what is your final
> > >> >> proposal right now. For example, I'm not completely following your
> > >> >> "compromise
> > >> >> of sorts": are you suggesting that we still add overloading
> functions
> > >> and
> > >> >> add a config that will be applied to all overload functions without
> > the
> > >> >> timeout, while for other overloaded functions with the timeout
> value
> > >> the
> > >> >> config will be ignored?
> > >> >>
> > >> >>
> > >> >> Guozhang
> > >> >>
> > >> >> On Fri, Mar 30, 2018 at 8:36 PM, Richard Yu <
> > >> yohan.richard...@gmail.com>
> > >> >> wrote:
> > >> >>
> > >> >> > On a side note, I have noticed that the several other methods in
> > >> classes
> > >> >> > such as StoreChangeLogReader in Streams calls position() which
> > causes
> > >> >> tests
> > >> >> > to 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Hi John,

I think that you could finish your PR that corresponds with KIP-288 and
merge it. I can finish my side of the work afterwards.

On another note, adding an asynchronized version of poll() would make
sense, particularily since the current version of Kafka does not support it.

Thanks
Richar

On Tue, Apr 17, 2018 at 12:30 PM, John Roesler  wrote:

> Cross-pollinating from some discussion we've had on KIP-288,
>
> I think there's a good reason that poll() takes a timeout when none of the
> other methods do, and it's relevant to this discussion. The timeout in
> poll() is effectively implementing a long-poll API (on the client side, so
> it's not really long-poll, but the programmer-facing behavior is the same).
> The timeout isn't really bounding the execution time of the method, but
> instead giving a max time that callers are willing to wait around and see
> if any results show up.
>
> If I understand the code sufficiently, it would be perfectly reasonable for
> a caller to use a timeout of 0 to implement async poll, it would just mean
> that KafkaConsumer would just check on each call if there's a response
> ready and if not, fire off a new request without waiting for a response.
>
> As such, it seems inappropriate to throw a ClientTimeoutException from
> poll(), except possibly if the initial phase of ensuring an assignment
> times out. We wouldn't want the method contract to be "returns a non-empty
> collection or throws a ClientTimeoutException"
>
> Now, I'm wondering if we should actually consider one of my rejected
> alternatives, to treat the "operation timeout" as a separate parameter from
> the "long-poll time". Or maybe adding an "asyncPoll(timeout, time unit)"
> that only uses the timeout to bound metadata updates and otherwise behaves
> like the current "poll(0)".
>
> Thanks,
> -John
>
> On Tue, Apr 17, 2018 at 2:05 PM, John Roesler  wrote:
>
> > Hey Richard,
> >
> > As you noticed, the newly introduced KIP-288 overlaps with this one.
> Sorry
> > for stepping on your toes... How would you like to proceed? I'm happy to
> > "close" KIP-288 in deference to this KIP.
> >
> > With respect to poll(), reading this discussion gave me a new idea for
> > providing a non-breaking update path... What if we introduce a new
> variant
> > 'poll(long timeout, TimeUnit unit)' that displays the new, desired
> > behavior, and just leave the old method alone?
> >
> > Thanks,
> > -John
> >
> > On Tue, Apr 17, 2018 at 12:09 PM, Richard Yu  >
> > wrote:
> >
> >> Hi all,
> >>
> >> If possible, would a committer please review?
> >>
> >> Thanks
> >>
> >> On Sun, Apr 1, 2018 at 7:24 PM, Richard Yu 
> >> wrote:
> >>
> >> > Hi Guozhang,
> >> >
> >> > I have clarified the KIP a bit to account for Becket's suggestion on
> >> > ClientTimeoutException.
> >> > About adding an extra config, you were right about my intentions. I am
> >> > just wondering if the config
> >> > should be included, since Ismael seems to favor an extra
> configuration,
> >> >
> >> > Thanks,
> >> > Richard
> >> >
> >> > On Sun, Apr 1, 2018 at 5:35 PM, Guozhang Wang 
> >> wrote:
> >> >
> >> >> Hi Richard,
> >> >>
> >> >> Regarding the streams side changes, we plan to incorporate with the
> new
> >> >> APIs once the KIP is done, which is only internal code changes and
> >> hence
> >> >> do
> >> >> not need to include in the KIP.
> >> >>
> >> >> Could you update the KIP because it has been quite obsoleted from the
> >> >> discussed topics, and I'm a bit loosing track on what is your final
> >> >> proposal right now. For example, I'm not completely following your
> >> >> "compromise
> >> >> of sorts": are you suggesting that we still add overloading functions
> >> and
> >> >> add a config that will be applied to all overload functions without
> the
> >> >> timeout, while for other overloaded functions with the timeout value
> >> the
> >> >> config will be ignored?
> >> >>
> >> >>
> >> >> Guozhang
> >> >>
> >> >> On Fri, Mar 30, 2018 at 8:36 PM, Richard Yu <
> >> yohan.richard...@gmail.com>
> >> >> wrote:
> >> >>
> >> >> > On a side note, I have noticed that the several other methods in
> >> classes
> >> >> > such as StoreChangeLogReader in Streams calls position() which
> causes
> >> >> tests
> >> >> > to hang. It might be out of the scope of the KIP, but should I also
> >> >> change
> >> >> > the methods which use position() as a callback to at the very least
> >> >> prevent
> >> >> > the tests from hanging? This issue might be out of the KIP, but I
> >> >> prefer it
> >> >> > if we could at least make my PR pass the Jenkins Q
> >> >> >
> >> >> > Thanks
> >> >> >
> >> >> > On Fri, Mar 30, 2018 at 8:24 PM, Richard Yu <
> >> yohan.richard...@gmail.com
> >> >> >
> >> >> > wrote:
> >> >> >
> >> >> > > Thanks for the review Becket.
> >> >> > >
> >> >> > > About the methods beginningOffsets(), endOffsets(), ...:
> >> >> > > I took a look 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[John Roesler]

Cross-pollinating from some discussion we've had on KIP-288,

I think there's a good reason that poll() takes a timeout when none of the
other methods do, and it's relevant to this discussion. The timeout in
poll() is effectively implementing a long-poll API (on the client side, so
it's not really long-poll, but the programmer-facing behavior is the same).
The timeout isn't really bounding the execution time of the method, but
instead giving a max time that callers are willing to wait around and see
if any results show up.

If I understand the code sufficiently, it would be perfectly reasonable for
a caller to use a timeout of 0 to implement async poll, it would just mean
that KafkaConsumer would just check on each call if there's a response
ready and if not, fire off a new request without waiting for a response.

As such, it seems inappropriate to throw a ClientTimeoutException from
poll(), except possibly if the initial phase of ensuring an assignment
times out. We wouldn't want the method contract to be "returns a non-empty
collection or throws a ClientTimeoutException"

Now, I'm wondering if we should actually consider one of my rejected
alternatives, to treat the "operation timeout" as a separate parameter from
the "long-poll time". Or maybe adding an "asyncPoll(timeout, time unit)"
that only uses the timeout to bound metadata updates and otherwise behaves
like the current "poll(0)".

Thanks,
-John

On Tue, Apr 17, 2018 at 2:05 PM, John Roesler  wrote:

> Hey Richard,
>
> As you noticed, the newly introduced KIP-288 overlaps with this one. Sorry
> for stepping on your toes... How would you like to proceed? I'm happy to
> "close" KIP-288 in deference to this KIP.
>
> With respect to poll(), reading this discussion gave me a new idea for
> providing a non-breaking update path... What if we introduce a new variant
> 'poll(long timeout, TimeUnit unit)' that displays the new, desired
> behavior, and just leave the old method alone?
>
> Thanks,
> -John
>
> On Tue, Apr 17, 2018 at 12:09 PM, Richard Yu 
> wrote:
>
>> Hi all,
>>
>> If possible, would a committer please review?
>>
>> Thanks
>>
>> On Sun, Apr 1, 2018 at 7:24 PM, Richard Yu 
>> wrote:
>>
>> > Hi Guozhang,
>> >
>> > I have clarified the KIP a bit to account for Becket's suggestion on
>> > ClientTimeoutException.
>> > About adding an extra config, you were right about my intentions. I am
>> > just wondering if the config
>> > should be included, since Ismael seems to favor an extra configuration,
>> >
>> > Thanks,
>> > Richard
>> >
>> > On Sun, Apr 1, 2018 at 5:35 PM, Guozhang Wang 
>> wrote:
>> >
>> >> Hi Richard,
>> >>
>> >> Regarding the streams side changes, we plan to incorporate with the new
>> >> APIs once the KIP is done, which is only internal code changes and
>> hence
>> >> do
>> >> not need to include in the KIP.
>> >>
>> >> Could you update the KIP because it has been quite obsoleted from the
>> >> discussed topics, and I'm a bit loosing track on what is your final
>> >> proposal right now. For example, I'm not completely following your
>> >> "compromise
>> >> of sorts": are you suggesting that we still add overloading functions
>> and
>> >> add a config that will be applied to all overload functions without the
>> >> timeout, while for other overloaded functions with the timeout value
>> the
>> >> config will be ignored?
>> >>
>> >>
>> >> Guozhang
>> >>
>> >> On Fri, Mar 30, 2018 at 8:36 PM, Richard Yu <
>> yohan.richard...@gmail.com>
>> >> wrote:
>> >>
>> >> > On a side note, I have noticed that the several other methods in
>> classes
>> >> > such as StoreChangeLogReader in Streams calls position() which causes
>> >> tests
>> >> > to hang. It might be out of the scope of the KIP, but should I also
>> >> change
>> >> > the methods which use position() as a callback to at the very least
>> >> prevent
>> >> > the tests from hanging? This issue might be out of the KIP, but I
>> >> prefer it
>> >> > if we could at least make my PR pass the Jenkins Q
>> >> >
>> >> > Thanks
>> >> >
>> >> > On Fri, Mar 30, 2018 at 8:24 PM, Richard Yu <
>> yohan.richard...@gmail.com
>> >> >
>> >> > wrote:
>> >> >
>> >> > > Thanks for the review Becket.
>> >> > >
>> >> > > About the methods beginningOffsets(), endOffsets(), ...:
>> >> > > I took a look through the code of KafkaConsumer, but after looking
>> >> > through
>> >> > > the offsetsByTimes() method
>> >> > > and its callbacks in Fetcher, I think these methods already block
>> for
>> >> a
>> >> > > set period of time. I know that there
>> >> > > is a chance that the offsets methods in KafkaConsumer might be like
>> >> poll
>> >> > > (that is one section of the method
>> >> > > honors the timeout while another -- updateFetchPositions -- does
>> not).
>> >> > > However, I don't think that this is the
>> >> > > case with offsetsByTimes since the callbacks that I checked does
>> not
>> >> seem
>> >> > > to hang.

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[John Roesler]

Hey Richard,

As you noticed, the newly introduced KIP-288 overlaps with this one. Sorry
for stepping on your toes... How would you like to proceed? I'm happy to
"close" KIP-288 in deference to this KIP.

With respect to poll(), reading this discussion gave me a new idea for
providing a non-breaking update path... What if we introduce a new variant
'poll(long timeout, TimeUnit unit)' that displays the new, desired
behavior, and just leave the old method alone?

Thanks,
-John

On Tue, Apr 17, 2018 at 12:09 PM, Richard Yu 
wrote:

> Hi all,
>
> If possible, would a committer please review?
>
> Thanks
>
> On Sun, Apr 1, 2018 at 7:24 PM, Richard Yu 
> wrote:
>
> > Hi Guozhang,
> >
> > I have clarified the KIP a bit to account for Becket's suggestion on
> > ClientTimeoutException.
> > About adding an extra config, you were right about my intentions. I am
> > just wondering if the config
> > should be included, since Ismael seems to favor an extra configuration,
> >
> > Thanks,
> > Richard
> >
> > On Sun, Apr 1, 2018 at 5:35 PM, Guozhang Wang 
> wrote:
> >
> >> Hi Richard,
> >>
> >> Regarding the streams side changes, we plan to incorporate with the new
> >> APIs once the KIP is done, which is only internal code changes and hence
> >> do
> >> not need to include in the KIP.
> >>
> >> Could you update the KIP because it has been quite obsoleted from the
> >> discussed topics, and I'm a bit loosing track on what is your final
> >> proposal right now. For example, I'm not completely following your
> >> "compromise
> >> of sorts": are you suggesting that we still add overloading functions
> and
> >> add a config that will be applied to all overload functions without the
> >> timeout, while for other overloaded functions with the timeout value the
> >> config will be ignored?
> >>
> >>
> >> Guozhang
> >>
> >> On Fri, Mar 30, 2018 at 8:36 PM, Richard Yu  >
> >> wrote:
> >>
> >> > On a side note, I have noticed that the several other methods in
> classes
> >> > such as StoreChangeLogReader in Streams calls position() which causes
> >> tests
> >> > to hang. It might be out of the scope of the KIP, but should I also
> >> change
> >> > the methods which use position() as a callback to at the very least
> >> prevent
> >> > the tests from hanging? This issue might be out of the KIP, but I
> >> prefer it
> >> > if we could at least make my PR pass the Jenkins Q
> >> >
> >> > Thanks
> >> >
> >> > On Fri, Mar 30, 2018 at 8:24 PM, Richard Yu <
> yohan.richard...@gmail.com
> >> >
> >> > wrote:
> >> >
> >> > > Thanks for the review Becket.
> >> > >
> >> > > About the methods beginningOffsets(), endOffsets(), ...:
> >> > > I took a look through the code of KafkaConsumer, but after looking
> >> > through
> >> > > the offsetsByTimes() method
> >> > > and its callbacks in Fetcher, I think these methods already block
> for
> >> a
> >> > > set period of time. I know that there
> >> > > is a chance that the offsets methods in KafkaConsumer might be like
> >> poll
> >> > > (that is one section of the method
> >> > > honors the timeout while another -- updateFetchPositions -- does
> not).
> >> > > However, I don't think that this is the
> >> > > case with offsetsByTimes since the callbacks that I checked does not
> >> seem
> >> > > to hang.
> >> > >
> >> > > The clarity of the exception message is a problem. I thought your
> >> > > suggestion there was reasonable. I included
> >> > > it in the KIP.
> >> > >
> >> > > And on another note, I have noticed that several people has voiced
> the
> >> > > opinion that adding a config might
> >> > > be advisable in relation to adding an extra parameter. I think that
> we
> >> > can
> >> > > have a compromise of sorts: some
> >> > > methods in KafkaConsumer are relatively similar -- for example,
> >> > position()
> >> > > and committed() both call
> >> > > updateFetchPositions(). I think that we could use the same config
> for
> >> > > these method as a default timeout if
> >> > > the user does not provide one. On the other hand, if they wish to
> >> specify
> >> > > a longer or shorter blocking time,
> >> > > they have the option of changing the timeout. (I included the config
> >> as
> >> > an
> >> > > alternative in the KIP) WDYT?
> >> > >
> >> > > Thanks,
> >> > > Richard
> >> > >
> >> > >
> >> > > On Fri, Mar 30, 2018 at 1:26 AM, Becket Qin 
> >> > wrote:
> >> > >
> >> > >> Glad to see the KIP, Richard. This has been a really long pending
> >> issue.
> >> > >>
> >> > >> The original arguments from Jay for using config, such as
> >> max.block.ms,
> >> > >> instead of using timeout parameters was that people will always
> hard
> >> > code
> >> > >> the timeout, and the hard coded timeout is rarely correct because
> it
> >> has
> >> > >> to
> >> > >> consider different scenarios. For example, users may receive
> timeout
> >> > >> exception when the group coordinator 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Hi all,

If possible, would a committer please review?

Thanks

On Sun, Apr 1, 2018 at 7:24 PM, Richard Yu 
wrote:

> Hi Guozhang,
>
> I have clarified the KIP a bit to account for Becket's suggestion on
> ClientTimeoutException.
> About adding an extra config, you were right about my intentions. I am
> just wondering if the config
> should be included, since Ismael seems to favor an extra configuration,
>
> Thanks,
> Richard
>
> On Sun, Apr 1, 2018 at 5:35 PM, Guozhang Wang  wrote:
>
>> Hi Richard,
>>
>> Regarding the streams side changes, we plan to incorporate with the new
>> APIs once the KIP is done, which is only internal code changes and hence
>> do
>> not need to include in the KIP.
>>
>> Could you update the KIP because it has been quite obsoleted from the
>> discussed topics, and I'm a bit loosing track on what is your final
>> proposal right now. For example, I'm not completely following your
>> "compromise
>> of sorts": are you suggesting that we still add overloading functions and
>> add a config that will be applied to all overload functions without the
>> timeout, while for other overloaded functions with the timeout value the
>> config will be ignored?
>>
>>
>> Guozhang
>>
>> On Fri, Mar 30, 2018 at 8:36 PM, Richard Yu 
>> wrote:
>>
>> > On a side note, I have noticed that the several other methods in classes
>> > such as StoreChangeLogReader in Streams calls position() which causes
>> tests
>> > to hang. It might be out of the scope of the KIP, but should I also
>> change
>> > the methods which use position() as a callback to at the very least
>> prevent
>> > the tests from hanging? This issue might be out of the KIP, but I
>> prefer it
>> > if we could at least make my PR pass the Jenkins Q
>> >
>> > Thanks
>> >
>> > On Fri, Mar 30, 2018 at 8:24 PM, Richard Yu > >
>> > wrote:
>> >
>> > > Thanks for the review Becket.
>> > >
>> > > About the methods beginningOffsets(), endOffsets(), ...:
>> > > I took a look through the code of KafkaConsumer, but after looking
>> > through
>> > > the offsetsByTimes() method
>> > > and its callbacks in Fetcher, I think these methods already block for
>> a
>> > > set period of time. I know that there
>> > > is a chance that the offsets methods in KafkaConsumer might be like
>> poll
>> > > (that is one section of the method
>> > > honors the timeout while another -- updateFetchPositions -- does not).
>> > > However, I don't think that this is the
>> > > case with offsetsByTimes since the callbacks that I checked does not
>> seem
>> > > to hang.
>> > >
>> > > The clarity of the exception message is a problem. I thought your
>> > > suggestion there was reasonable. I included
>> > > it in the KIP.
>> > >
>> > > And on another note, I have noticed that several people has voiced the
>> > > opinion that adding a config might
>> > > be advisable in relation to adding an extra parameter. I think that we
>> > can
>> > > have a compromise of sorts: some
>> > > methods in KafkaConsumer are relatively similar -- for example,
>> > position()
>> > > and committed() both call
>> > > updateFetchPositions(). I think that we could use the same config for
>> > > these method as a default timeout if
>> > > the user does not provide one. On the other hand, if they wish to
>> specify
>> > > a longer or shorter blocking time,
>> > > they have the option of changing the timeout. (I included the config
>> as
>> > an
>> > > alternative in the KIP) WDYT?
>> > >
>> > > Thanks,
>> > > Richard
>> > >
>> > >
>> > > On Fri, Mar 30, 2018 at 1:26 AM, Becket Qin 
>> > wrote:
>> > >
>> > >> Glad to see the KIP, Richard. This has been a really long pending
>> issue.
>> > >>
>> > >> The original arguments from Jay for using config, such as
>> max.block.ms,
>> > >> instead of using timeout parameters was that people will always hard
>> > code
>> > >> the timeout, and the hard coded timeout is rarely correct because it
>> has
>> > >> to
>> > >> consider different scenarios. For example, users may receive timeout
>> > >> exception when the group coordinator moves. Having a configuration
>> with
>> > >> some reasonable default value will make users' life easier.
>> > >>
>> > >> That said, in practice, it seems more useful to have timeout
>> parameters.
>> > >> We
>> > >> have seen some library, using the consumers internally, needs to
>> provide
>> > >> an
>> > >> external flexible timeout interface. Also, user can easily hard code
>> a
>> > >> value to get the same as a config based solution.
>> > >>
>> > >> The KIP looks good overall. A few comments:
>> > >>
>> > >> 1. There are a few other blocking methods that are not included, e.g.
>> > >> offsetsForTimes(), beginningOffsets(), endOffsets(). Is there any
>> > reason?
>> > >>
>> > >> 2. I am wondering can we take the KIP as a chance to clean up our
>> > timeout
>> > >> exception(s)? More specifically, instead of reusing 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Hi Guozhang,

I have clarified the KIP a bit to account for Becket's suggestion on
ClientTimeoutException.
About adding an extra config, you were right about my intentions. I am just
wondering if the config
should be included, since Ismael seems to favor an extra configuration,

Thanks,
Richard

On Sun, Apr 1, 2018 at 5:35 PM, Guozhang Wang  wrote:

> Hi Richard,
>
> Regarding the streams side changes, we plan to incorporate with the new
> APIs once the KIP is done, which is only internal code changes and hence do
> not need to include in the KIP.
>
> Could you update the KIP because it has been quite obsoleted from the
> discussed topics, and I'm a bit loosing track on what is your final
> proposal right now. For example, I'm not completely following your
> "compromise
> of sorts": are you suggesting that we still add overloading functions and
> add a config that will be applied to all overload functions without the
> timeout, while for other overloaded functions with the timeout value the
> config will be ignored?
>
>
> Guozhang
>
> On Fri, Mar 30, 2018 at 8:36 PM, Richard Yu 
> wrote:
>
> > On a side note, I have noticed that the several other methods in classes
> > such as StoreChangeLogReader in Streams calls position() which causes
> tests
> > to hang. It might be out of the scope of the KIP, but should I also
> change
> > the methods which use position() as a callback to at the very least
> prevent
> > the tests from hanging? This issue might be out of the KIP, but I prefer
> it
> > if we could at least make my PR pass the Jenkins Q
> >
> > Thanks
> >
> > On Fri, Mar 30, 2018 at 8:24 PM, Richard Yu 
> > wrote:
> >
> > > Thanks for the review Becket.
> > >
> > > About the methods beginningOffsets(), endOffsets(), ...:
> > > I took a look through the code of KafkaConsumer, but after looking
> > through
> > > the offsetsByTimes() method
> > > and its callbacks in Fetcher, I think these methods already block for a
> > > set period of time. I know that there
> > > is a chance that the offsets methods in KafkaConsumer might be like
> poll
> > > (that is one section of the method
> > > honors the timeout while another -- updateFetchPositions -- does not).
> > > However, I don't think that this is the
> > > case with offsetsByTimes since the callbacks that I checked does not
> seem
> > > to hang.
> > >
> > > The clarity of the exception message is a problem. I thought your
> > > suggestion there was reasonable. I included
> > > it in the KIP.
> > >
> > > And on another note, I have noticed that several people has voiced the
> > > opinion that adding a config might
> > > be advisable in relation to adding an extra parameter. I think that we
> > can
> > > have a compromise of sorts: some
> > > methods in KafkaConsumer are relatively similar -- for example,
> > position()
> > > and committed() both call
> > > updateFetchPositions(). I think that we could use the same config for
> > > these method as a default timeout if
> > > the user does not provide one. On the other hand, if they wish to
> specify
> > > a longer or shorter blocking time,
> > > they have the option of changing the timeout. (I included the config as
> > an
> > > alternative in the KIP) WDYT?
> > >
> > > Thanks,
> > > Richard
> > >
> > >
> > > On Fri, Mar 30, 2018 at 1:26 AM, Becket Qin 
> > wrote:
> > >
> > >> Glad to see the KIP, Richard. This has been a really long pending
> issue.
> > >>
> > >> The original arguments from Jay for using config, such as
> max.block.ms,
> > >> instead of using timeout parameters was that people will always hard
> > code
> > >> the timeout, and the hard coded timeout is rarely correct because it
> has
> > >> to
> > >> consider different scenarios. For example, users may receive timeout
> > >> exception when the group coordinator moves. Having a configuration
> with
> > >> some reasonable default value will make users' life easier.
> > >>
> > >> That said, in practice, it seems more useful to have timeout
> parameters.
> > >> We
> > >> have seen some library, using the consumers internally, needs to
> provide
> > >> an
> > >> external flexible timeout interface. Also, user can easily hard code a
> > >> value to get the same as a config based solution.
> > >>
> > >> The KIP looks good overall. A few comments:
> > >>
> > >> 1. There are a few other blocking methods that are not included, e.g.
> > >> offsetsForTimes(), beginningOffsets(), endOffsets(). Is there any
> > reason?
> > >>
> > >> 2. I am wondering can we take the KIP as a chance to clean up our
> > timeout
> > >> exception(s)? More specifically, instead of reusing TimeoutException,
> > can
> > >> we introduce a new ClientTimeoutException with different causes, e.g.
> > >> UnknownTopicOrPartition, RequestTimeout, LeaderNotAvailable, etc.
> > >> As of now, the TimeoutException is used in the following three cases:
> > >>
> > >>1. TimeoutException is a 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Guozhang Wang]

Hi Richard,

Regarding the streams side changes, we plan to incorporate with the new
APIs once the KIP is done, which is only internal code changes and hence do
not need to include in the KIP.

Could you update the KIP because it has been quite obsoleted from the
discussed topics, and I'm a bit loosing track on what is your final
proposal right now. For example, I'm not completely following your "compromise
of sorts": are you suggesting that we still add overloading functions and
add a config that will be applied to all overload functions without the
timeout, while for other overloaded functions with the timeout value the
config will be ignored?


Guozhang

On Fri, Mar 30, 2018 at 8:36 PM, Richard Yu 
wrote:

> On a side note, I have noticed that the several other methods in classes
> such as StoreChangeLogReader in Streams calls position() which causes tests
> to hang. It might be out of the scope of the KIP, but should I also change
> the methods which use position() as a callback to at the very least prevent
> the tests from hanging? This issue might be out of the KIP, but I prefer it
> if we could at least make my PR pass the Jenkins Q
>
> Thanks
>
> On Fri, Mar 30, 2018 at 8:24 PM, Richard Yu 
> wrote:
>
> > Thanks for the review Becket.
> >
> > About the methods beginningOffsets(), endOffsets(), ...:
> > I took a look through the code of KafkaConsumer, but after looking
> through
> > the offsetsByTimes() method
> > and its callbacks in Fetcher, I think these methods already block for a
> > set period of time. I know that there
> > is a chance that the offsets methods in KafkaConsumer might be like poll
> > (that is one section of the method
> > honors the timeout while another -- updateFetchPositions -- does not).
> > However, I don't think that this is the
> > case with offsetsByTimes since the callbacks that I checked does not seem
> > to hang.
> >
> > The clarity of the exception message is a problem. I thought your
> > suggestion there was reasonable. I included
> > it in the KIP.
> >
> > And on another note, I have noticed that several people has voiced the
> > opinion that adding a config might
> > be advisable in relation to adding an extra parameter. I think that we
> can
> > have a compromise of sorts: some
> > methods in KafkaConsumer are relatively similar -- for example,
> position()
> > and committed() both call
> > updateFetchPositions(). I think that we could use the same config for
> > these method as a default timeout if
> > the user does not provide one. On the other hand, if they wish to specify
> > a longer or shorter blocking time,
> > they have the option of changing the timeout. (I included the config as
> an
> > alternative in the KIP) WDYT?
> >
> > Thanks,
> > Richard
> >
> >
> > On Fri, Mar 30, 2018 at 1:26 AM, Becket Qin 
> wrote:
> >
> >> Glad to see the KIP, Richard. This has been a really long pending issue.
> >>
> >> The original arguments from Jay for using config, such as max.block.ms,
> >> instead of using timeout parameters was that people will always hard
> code
> >> the timeout, and the hard coded timeout is rarely correct because it has
> >> to
> >> consider different scenarios. For example, users may receive timeout
> >> exception when the group coordinator moves. Having a configuration with
> >> some reasonable default value will make users' life easier.
> >>
> >> That said, in practice, it seems more useful to have timeout parameters.
> >> We
> >> have seen some library, using the consumers internally, needs to provide
> >> an
> >> external flexible timeout interface. Also, user can easily hard code a
> >> value to get the same as a config based solution.
> >>
> >> The KIP looks good overall. A few comments:
> >>
> >> 1. There are a few other blocking methods that are not included, e.g.
> >> offsetsForTimes(), beginningOffsets(), endOffsets(). Is there any
> reason?
> >>
> >> 2. I am wondering can we take the KIP as a chance to clean up our
> timeout
> >> exception(s)? More specifically, instead of reusing TimeoutException,
> can
> >> we introduce a new ClientTimeoutException with different causes, e.g.
> >> UnknownTopicOrPartition, RequestTimeout, LeaderNotAvailable, etc.
> >> As of now, the TimeoutException is used in the following three cases:
> >>
> >>1. TimeoutException is a subclass of ApiException which indicates the
> >>exception was returned by the broker. The TimeoutException was
> >> initially
> >>returned by the leaders when replication was not done within the
> >> specified
> >>timeout in the ProduceRequest. It has an error code of 7, which is
> >> returned
> >>by the broker.
> >>2. When we migrate to Java clients, in Errors definition, we extended
> >> it
> >>to indicate request timeout, i.e. a request was sent but the response
> >> was
> >>not received before timeout. In this case, the clients did not have a
> >>return code from the 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

On a side note, I have noticed that the several other methods in classes
such as StoreChangeLogReader in Streams calls position() which causes tests
to hang. It might be out of the scope of the KIP, but should I also change
the methods which use position() as a callback to at the very least prevent
the tests from hanging? This issue might be out of the KIP, but I prefer it
if we could at least make my PR pass the Jenkins Q

Thanks

On Fri, Mar 30, 2018 at 8:24 PM, Richard Yu 
wrote:

> Thanks for the review Becket.
>
> About the methods beginningOffsets(), endOffsets(), ...:
> I took a look through the code of KafkaConsumer, but after looking through
> the offsetsByTimes() method
> and its callbacks in Fetcher, I think these methods already block for a
> set period of time. I know that there
> is a chance that the offsets methods in KafkaConsumer might be like poll
> (that is one section of the method
> honors the timeout while another -- updateFetchPositions -- does not).
> However, I don't think that this is the
> case with offsetsByTimes since the callbacks that I checked does not seem
> to hang.
>
> The clarity of the exception message is a problem. I thought your
> suggestion there was reasonable. I included
> it in the KIP.
>
> And on another note, I have noticed that several people has voiced the
> opinion that adding a config might
> be advisable in relation to adding an extra parameter. I think that we can
> have a compromise of sorts: some
> methods in KafkaConsumer are relatively similar -- for example, position()
> and committed() both call
> updateFetchPositions(). I think that we could use the same config for
> these method as a default timeout if
> the user does not provide one. On the other hand, if they wish to specify
> a longer or shorter blocking time,
> they have the option of changing the timeout. (I included the config as an
> alternative in the KIP) WDYT?
>
> Thanks,
> Richard
>
>
> On Fri, Mar 30, 2018 at 1:26 AM, Becket Qin  wrote:
>
>> Glad to see the KIP, Richard. This has been a really long pending issue.
>>
>> The original arguments from Jay for using config, such as max.block.ms,
>> instead of using timeout parameters was that people will always hard code
>> the timeout, and the hard coded timeout is rarely correct because it has
>> to
>> consider different scenarios. For example, users may receive timeout
>> exception when the group coordinator moves. Having a configuration with
>> some reasonable default value will make users' life easier.
>>
>> That said, in practice, it seems more useful to have timeout parameters.
>> We
>> have seen some library, using the consumers internally, needs to provide
>> an
>> external flexible timeout interface. Also, user can easily hard code a
>> value to get the same as a config based solution.
>>
>> The KIP looks good overall. A few comments:
>>
>> 1. There are a few other blocking methods that are not included, e.g.
>> offsetsForTimes(), beginningOffsets(), endOffsets(). Is there any reason?
>>
>> 2. I am wondering can we take the KIP as a chance to clean up our timeout
>> exception(s)? More specifically, instead of reusing TimeoutException, can
>> we introduce a new ClientTimeoutException with different causes, e.g.
>> UnknownTopicOrPartition, RequestTimeout, LeaderNotAvailable, etc.
>> As of now, the TimeoutException is used in the following three cases:
>>
>>1. TimeoutException is a subclass of ApiException which indicates the
>>exception was returned by the broker. The TimeoutException was
>> initially
>>returned by the leaders when replication was not done within the
>> specified
>>timeout in the ProduceRequest. It has an error code of 7, which is
>> returned
>>by the broker.
>>2. When we migrate to Java clients, in Errors definition, we extended
>> it
>>to indicate request timeout, i.e. a request was sent but the response
>> was
>>not received before timeout. In this case, the clients did not have a
>>return code from the broker.
>>3. Later at some point, we started to use the TimeoutException for
>>clients method call timeout. It is neither related to any broker
>> returned
>>error code, nor to request timeout on the wire.
>>
>> Due to the various interpretations, users can easily be confused. As an
>> example, when a timeout is thrown with "Failed to refresh metadata in X
>> ms", it is hard to tell what exactly happened. Since we are changing the
>> API here, it would be good to avoid introducing more ambiguity and see
>> whether this can be improved. It would be at least one step forward to
>> remove the usage of case 3.
>>
>> Thanks,
>>
>> Jiangjie (Becket) Qin
>>
>>
>>
>>
>> On Mon, Mar 26, 2018 at 5:50 PM, Guozhang Wang 
>> wrote:
>>
>> > @Richard: TimeoutException inherits from RetriableException which
>> inherits
>> > from ApiException. So users should explicitly try to capture
>> > RetriableException in 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Thanks for the review Becket.

About the methods beginningOffsets(), endOffsets(), ...:
I took a look through the code of KafkaConsumer, but after looking through
the offsetsByTimes() method
and its callbacks in Fetcher, I think these methods already block for a set
period of time. I know that there
is a chance that the offsets methods in KafkaConsumer might be like poll
(that is one section of the method
honors the timeout while another -- updateFetchPositions -- does not).
However, I don't think that this is the
case with offsetsByTimes since the callbacks that I checked does not seem
to hang.

The clarity of the exception message is a problem. I thought your
suggestion there was reasonable. I included
it in the KIP.

And on another note, I have noticed that several people has voiced the
opinion that adding a config might
be advisable in relation to adding an extra parameter. I think that we can
have a compromise of sorts: some
methods in KafkaConsumer are relatively similar -- for example, position()
and committed() both call
updateFetchPositions(). I think that we could use the same config for these
method as a default timeout if
the user does not provide one. On the other hand, if they wish to specify a
longer or shorter blocking time,
they have the option of changing the timeout. (I included the config as an
alternative in the KIP) WDYT?

Thanks,
Richard


On Fri, Mar 30, 2018 at 1:26 AM, Becket Qin  wrote:

> Glad to see the KIP, Richard. This has been a really long pending issue.
>
> The original arguments from Jay for using config, such as max.block.ms,
> instead of using timeout parameters was that people will always hard code
> the timeout, and the hard coded timeout is rarely correct because it has to
> consider different scenarios. For example, users may receive timeout
> exception when the group coordinator moves. Having a configuration with
> some reasonable default value will make users' life easier.
>
> That said, in practice, it seems more useful to have timeout parameters. We
> have seen some library, using the consumers internally, needs to provide an
> external flexible timeout interface. Also, user can easily hard code a
> value to get the same as a config based solution.
>
> The KIP looks good overall. A few comments:
>
> 1. There are a few other blocking methods that are not included, e.g.
> offsetsForTimes(), beginningOffsets(), endOffsets(). Is there any reason?
>
> 2. I am wondering can we take the KIP as a chance to clean up our timeout
> exception(s)? More specifically, instead of reusing TimeoutException, can
> we introduce a new ClientTimeoutException with different causes, e.g.
> UnknownTopicOrPartition, RequestTimeout, LeaderNotAvailable, etc.
> As of now, the TimeoutException is used in the following three cases:
>
>1. TimeoutException is a subclass of ApiException which indicates the
>exception was returned by the broker. The TimeoutException was initially
>returned by the leaders when replication was not done within the
> specified
>timeout in the ProduceRequest. It has an error code of 7, which is
> returned
>by the broker.
>2. When we migrate to Java clients, in Errors definition, we extended it
>to indicate request timeout, i.e. a request was sent but the response
> was
>not received before timeout. In this case, the clients did not have a
>return code from the broker.
>3. Later at some point, we started to use the TimeoutException for
>clients method call timeout. It is neither related to any broker
> returned
>error code, nor to request timeout on the wire.
>
> Due to the various interpretations, users can easily be confused. As an
> example, when a timeout is thrown with "Failed to refresh metadata in X
> ms", it is hard to tell what exactly happened. Since we are changing the
> API here, it would be good to avoid introducing more ambiguity and see
> whether this can be improved. It would be at least one step forward to
> remove the usage of case 3.
>
> Thanks,
>
> Jiangjie (Becket) Qin
>
>
>
>
> On Mon, Mar 26, 2018 at 5:50 PM, Guozhang Wang  wrote:
>
> > @Richard: TimeoutException inherits from RetriableException which
> inherits
> > from ApiException. So users should explicitly try to capture
> > RetriableException in their code and handle the exception.
> >
> > @Isamel, Ewen: I'm trying to push progress forward on this one, are we
> now
> > on the same page for using function parameters than configs?
> >
> >
> > Guozhang
> >
> >
> > On Fri, Mar 23, 2018 at 4:42 PM, Ismael Juma  wrote:
> >
> > > Hi Ewen,
> > >
> > > Yeah, I mentioned KAFKA-2391 where some of this was discussed. Jay was
> > > against having timeouts in the methods at the time. However, as Jason
> > said
> > > offline, we did end up with a timeout parameter in `poll`.
> > >
> > > Ismael
> > >
> > > On Fri, Mar 23, 2018 at 4:26 PM, Ewen Cheslack-Postava <
> > e...@confluent.io>
> > > wrote:

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Becket Qin]

Glad to see the KIP, Richard. This has been a really long pending issue.

The original arguments from Jay for using config, such as max.block.ms,
instead of using timeout parameters was that people will always hard code
the timeout, and the hard coded timeout is rarely correct because it has to
consider different scenarios. For example, users may receive timeout
exception when the group coordinator moves. Having a configuration with
some reasonable default value will make users' life easier.

That said, in practice, it seems more useful to have timeout parameters. We
have seen some library, using the consumers internally, needs to provide an
external flexible timeout interface. Also, user can easily hard code a
value to get the same as a config based solution.

The KIP looks good overall. A few comments:

1. There are a few other blocking methods that are not included, e.g.
offsetsForTimes(), beginningOffsets(), endOffsets(). Is there any reason?

2. I am wondering can we take the KIP as a chance to clean up our timeout
exception(s)? More specifically, instead of reusing TimeoutException, can
we introduce a new ClientTimeoutException with different causes, e.g.
UnknownTopicOrPartition, RequestTimeout, LeaderNotAvailable, etc.
As of now, the TimeoutException is used in the following three cases:

   1. TimeoutException is a subclass of ApiException which indicates the
   exception was returned by the broker. The TimeoutException was initially
   returned by the leaders when replication was not done within the specified
   timeout in the ProduceRequest. It has an error code of 7, which is returned
   by the broker.
   2. When we migrate to Java clients, in Errors definition, we extended it
   to indicate request timeout, i.e. a request was sent but the response was
   not received before timeout. In this case, the clients did not have a
   return code from the broker.
   3. Later at some point, we started to use the TimeoutException for
   clients method call timeout. It is neither related to any broker returned
   error code, nor to request timeout on the wire.

Due to the various interpretations, users can easily be confused. As an
example, when a timeout is thrown with "Failed to refresh metadata in X
ms", it is hard to tell what exactly happened. Since we are changing the
API here, it would be good to avoid introducing more ambiguity and see
whether this can be improved. It would be at least one step forward to
remove the usage of case 3.

Thanks,

Jiangjie (Becket) Qin




On Mon, Mar 26, 2018 at 5:50 PM, Guozhang Wang  wrote:

> @Richard: TimeoutException inherits from RetriableException which inherits
> from ApiException. So users should explicitly try to capture
> RetriableException in their code and handle the exception.
>
> @Isamel, Ewen: I'm trying to push progress forward on this one, are we now
> on the same page for using function parameters than configs?
>
>
> Guozhang
>
>
> On Fri, Mar 23, 2018 at 4:42 PM, Ismael Juma  wrote:
>
> > Hi Ewen,
> >
> > Yeah, I mentioned KAFKA-2391 where some of this was discussed. Jay was
> > against having timeouts in the methods at the time. However, as Jason
> said
> > offline, we did end up with a timeout parameter in `poll`.
> >
> > Ismael
> >
> > On Fri, Mar 23, 2018 at 4:26 PM, Ewen Cheslack-Postava <
> e...@confluent.io>
> > wrote:
> >
> > > Regarding the flexibility question, has someone tried to dig up the
> > > discussion of the new consumer APIs when they were being written? I
> > vaguely
> > > recall these exact questions about using APIs vs configs and
> flexibility
> > vs
> > > bloating the API surface area having already been discussed. (Not that
> we
> > > shouldn't revisit, just that it might also be a faster way to get to a
> > full
> > > understanding of the options, concerns, and tradeoffs).
> > >
> > > -Ewen
> > >
> > > On Thu, Mar 22, 2018 at 7:19 AM, Richard Yu <
> yohan.richard...@gmail.com>
> > > wrote:
> > >
> > > > I do have one question though: in the current KIP, throwing
> > > > TimeoutException to mark
> > > > that time limit is exceeded is applied to all new methods introduced
> in
> > > > this proposal.
> > > > However, how would users respond when a TimeoutException (since it is
> > > > considered
> > > > a RuntimeException)?
> > > >
> > > > Thanks,
> > > > Richard
> > > >
> > > >
> > > >
> > > > On Mon, Mar 19, 2018 at 6:10 PM, Richard Yu <
> > yohan.richard...@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi Ismael,
> > > > >
> > > > > You have a great point. Since most of the methods in this KIP have
> > > > similar
> > > > > callbacks (position() and committed() both use
> > fetchCommittedOffsets(),
> > > > > and
> > > > > commitSync() is similar to position(), except just updating
> offsets),
> > > the
> > > > > amount of time
> > > > > they block should be also about equal.
> > > > >
> > > > > However, I think that we need to take into account a couple of
> > things.
> > > > For
> > > 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Guozhang Wang]

@Richard: TimeoutException inherits from RetriableException which inherits
from ApiException. So users should explicitly try to capture
RetriableException in their code and handle the exception.

@Isamel, Ewen: I'm trying to push progress forward on this one, are we now
on the same page for using function parameters than configs?


Guozhang


On Fri, Mar 23, 2018 at 4:42 PM, Ismael Juma  wrote:

> Hi Ewen,
>
> Yeah, I mentioned KAFKA-2391 where some of this was discussed. Jay was
> against having timeouts in the methods at the time. However, as Jason said
> offline, we did end up with a timeout parameter in `poll`.
>
> Ismael
>
> On Fri, Mar 23, 2018 at 4:26 PM, Ewen Cheslack-Postava 
> wrote:
>
> > Regarding the flexibility question, has someone tried to dig up the
> > discussion of the new consumer APIs when they were being written? I
> vaguely
> > recall these exact questions about using APIs vs configs and flexibility
> vs
> > bloating the API surface area having already been discussed. (Not that we
> > shouldn't revisit, just that it might also be a faster way to get to a
> full
> > understanding of the options, concerns, and tradeoffs).
> >
> > -Ewen
> >
> > On Thu, Mar 22, 2018 at 7:19 AM, Richard Yu 
> > wrote:
> >
> > > I do have one question though: in the current KIP, throwing
> > > TimeoutException to mark
> > > that time limit is exceeded is applied to all new methods introduced in
> > > this proposal.
> > > However, how would users respond when a TimeoutException (since it is
> > > considered
> > > a RuntimeException)?
> > >
> > > Thanks,
> > > Richard
> > >
> > >
> > >
> > > On Mon, Mar 19, 2018 at 6:10 PM, Richard Yu <
> yohan.richard...@gmail.com>
> > > wrote:
> > >
> > > > Hi Ismael,
> > > >
> > > > You have a great point. Since most of the methods in this KIP have
> > > similar
> > > > callbacks (position() and committed() both use
> fetchCommittedOffsets(),
> > > > and
> > > > commitSync() is similar to position(), except just updating offsets),
> > the
> > > > amount of time
> > > > they block should be also about equal.
> > > >
> > > > However, I think that we need to take into account a couple of
> things.
> > > For
> > > > starters,
> > > > if the new methods were all reliant on one config, there is
> likelihood
> > > > that the
> > > > shortcomings for this approach would be similar to what we faced if
> we
> > > let
> > > > request.timeout.ms control all method timeouts. In comparison,
> adding
> > > > overloads
> > > > does not have this problem.
> > > >
> > > > If you have further thoughts, please let me know.
> > > >
> > > > Richard
> > > >
> > > >
> > > > On Mon, Mar 19, 2018 at 5:12 PM, Ismael Juma 
> > wrote:
> > > >
> > > >> Hi,
> > > >>
> > > >> An option that is not currently covered in the KIP is to have a
> > separate
> > > >> config max.block.ms, which is similar to the producer config with
> the
> > > >> same
> > > >> name. This came up during the KAFKA-2391 discussion. I think it's
> > clear
> > > >> that we can't rely on request.timeout.ms, so the decision is
> between
> > > >> adding
> > > >> overloads or adding a new config. People seemed to be leaning
> towards
> > > the
> > > >> latter in KAFKA-2391, but Jason makes a good point that the
> overloads
> > > are
> > > >> more flexible. A couple of questions from me:
> > > >>
> > > >> 1. Do we need the additional flexibility?
> > > >> 2. If we do, do we need it for every blocking method?
> > > >>
> > > >> Ismael
> > > >>
> > > >> On Mon, Mar 19, 2018 at 5:03 PM, Richard Yu <
> > yohan.richard...@gmail.com
> > > >
> > > >> wrote:
> > > >>
> > > >> > Hi Guozhang,
> > > >> >
> > > >> > I made some clarifications to KIP-266, namely:
> > > >> > 1. Stated more specifically that commitSync will accept user
> input.
> > > >> > 2. fetchCommittedOffsets(): Made its role in blocking more clear
> to
> > > the
> > > >> > reader.
> > > >> > 3. Sketched what would happen when time limit is exceeded.
> > > >> >
> > > >> > These changes should make the KIP easier to understand.
> > > >> >
> > > >> > Cheers,
> > > >> > Richard
> > > >> >
> > > >> > On Mon, Mar 19, 2018 at 9:33 AM, Guozhang Wang <
> wangg...@gmail.com>
> > > >> wrote:
> > > >> >
> > > >> > > Hi Richard,
> > > >> > >
> > > >> > > I made a pass over the KIP again, some more clarifications /
> > > comments:
> > > >> > >
> > > >> > > 1. seek() call itself is not blocking, only the following poll()
> > > call
> > > >> may
> > > >> > > be blocking as the actually metadata rq will happen.
> > > >> > >
> > > >> > > 2. I saw you did not include Consumer.partitionFor(),
> > > >> > > Consumer.OffsetAndTimestamp() and Consumer.listTopics() in your
> > KIP.
> > > >> > After
> > > >> > > a second thought, I think this may be a better idea to not
> tackle
> > > >> them in
> > > >> > > the same KIP, and probably we should consider whether we would
> > > change
> > > >> the
> > > >> > > behavior or 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Ismael Juma]

Hi Ewen,

Yeah, I mentioned KAFKA-2391 where some of this was discussed. Jay was
against having timeouts in the methods at the time. However, as Jason said
offline, we did end up with a timeout parameter in `poll`.

Ismael

On Fri, Mar 23, 2018 at 4:26 PM, Ewen Cheslack-Postava 
wrote:

> Regarding the flexibility question, has someone tried to dig up the
> discussion of the new consumer APIs when they were being written? I vaguely
> recall these exact questions about using APIs vs configs and flexibility vs
> bloating the API surface area having already been discussed. (Not that we
> shouldn't revisit, just that it might also be a faster way to get to a full
> understanding of the options, concerns, and tradeoffs).
>
> -Ewen
>
> On Thu, Mar 22, 2018 at 7:19 AM, Richard Yu 
> wrote:
>
> > I do have one question though: in the current KIP, throwing
> > TimeoutException to mark
> > that time limit is exceeded is applied to all new methods introduced in
> > this proposal.
> > However, how would users respond when a TimeoutException (since it is
> > considered
> > a RuntimeException)?
> >
> > Thanks,
> > Richard
> >
> >
> >
> > On Mon, Mar 19, 2018 at 6:10 PM, Richard Yu 
> > wrote:
> >
> > > Hi Ismael,
> > >
> > > You have a great point. Since most of the methods in this KIP have
> > similar
> > > callbacks (position() and committed() both use fetchCommittedOffsets(),
> > > and
> > > commitSync() is similar to position(), except just updating offsets),
> the
> > > amount of time
> > > they block should be also about equal.
> > >
> > > However, I think that we need to take into account a couple of things.
> > For
> > > starters,
> > > if the new methods were all reliant on one config, there is likelihood
> > > that the
> > > shortcomings for this approach would be similar to what we faced if we
> > let
> > > request.timeout.ms control all method timeouts. In comparison, adding
> > > overloads
> > > does not have this problem.
> > >
> > > If you have further thoughts, please let me know.
> > >
> > > Richard
> > >
> > >
> > > On Mon, Mar 19, 2018 at 5:12 PM, Ismael Juma 
> wrote:
> > >
> > >> Hi,
> > >>
> > >> An option that is not currently covered in the KIP is to have a
> separate
> > >> config max.block.ms, which is similar to the producer config with the
> > >> same
> > >> name. This came up during the KAFKA-2391 discussion. I think it's
> clear
> > >> that we can't rely on request.timeout.ms, so the decision is between
> > >> adding
> > >> overloads or adding a new config. People seemed to be leaning towards
> > the
> > >> latter in KAFKA-2391, but Jason makes a good point that the overloads
> > are
> > >> more flexible. A couple of questions from me:
> > >>
> > >> 1. Do we need the additional flexibility?
> > >> 2. If we do, do we need it for every blocking method?
> > >>
> > >> Ismael
> > >>
> > >> On Mon, Mar 19, 2018 at 5:03 PM, Richard Yu <
> yohan.richard...@gmail.com
> > >
> > >> wrote:
> > >>
> > >> > Hi Guozhang,
> > >> >
> > >> > I made some clarifications to KIP-266, namely:
> > >> > 1. Stated more specifically that commitSync will accept user input.
> > >> > 2. fetchCommittedOffsets(): Made its role in blocking more clear to
> > the
> > >> > reader.
> > >> > 3. Sketched what would happen when time limit is exceeded.
> > >> >
> > >> > These changes should make the KIP easier to understand.
> > >> >
> > >> > Cheers,
> > >> > Richard
> > >> >
> > >> > On Mon, Mar 19, 2018 at 9:33 AM, Guozhang Wang 
> > >> wrote:
> > >> >
> > >> > > Hi Richard,
> > >> > >
> > >> > > I made a pass over the KIP again, some more clarifications /
> > comments:
> > >> > >
> > >> > > 1. seek() call itself is not blocking, only the following poll()
> > call
> > >> may
> > >> > > be blocking as the actually metadata rq will happen.
> > >> > >
> > >> > > 2. I saw you did not include Consumer.partitionFor(),
> > >> > > Consumer.OffsetAndTimestamp() and Consumer.listTopics() in your
> KIP.
> > >> > After
> > >> > > a second thought, I think this may be a better idea to not tackle
> > >> them in
> > >> > > the same KIP, and probably we should consider whether we would
> > change
> > >> the
> > >> > > behavior or not in another discussion. So I agree to not include
> > them.
> > >> > >
> > >> > > 3. In your wiki you mentioned "Another change shall be made to
> > >> > > KafkaConsumer#poll(), due to its call to updateFetchPositions()
> > which
> > >> > > blocks indefinitely." This part may a bit obscure to most readers
> > >> who's
> > >> > not
> > >> > > familiar with the KafkaConsumer internals, could you please add
> more
> > >> > > elaborations. More specifically, I think the root causes of the
> > public
> > >> > APIs
> > >> > > mentioned are a bit different while the KIP's explanation sounds
> > like
> > >> > they
> > >> > > are due to the same reason:
> > >> > >
> > >> > > 3.1 fetchCommittedOffsets(): this 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Ewen Cheslack-Postava]

Regarding the flexibility question, has someone tried to dig up the
discussion of the new consumer APIs when they were being written? I vaguely
recall these exact questions about using APIs vs configs and flexibility vs
bloating the API surface area having already been discussed. (Not that we
shouldn't revisit, just that it might also be a faster way to get to a full
understanding of the options, concerns, and tradeoffs).

-Ewen

On Thu, Mar 22, 2018 at 7:19 AM, Richard Yu 
wrote:

> I do have one question though: in the current KIP, throwing
> TimeoutException to mark
> that time limit is exceeded is applied to all new methods introduced in
> this proposal.
> However, how would users respond when a TimeoutException (since it is
> considered
> a RuntimeException)?
>
> Thanks,
> Richard
>
>
>
> On Mon, Mar 19, 2018 at 6:10 PM, Richard Yu 
> wrote:
>
> > Hi Ismael,
> >
> > You have a great point. Since most of the methods in this KIP have
> similar
> > callbacks (position() and committed() both use fetchCommittedOffsets(),
> > and
> > commitSync() is similar to position(), except just updating offsets), the
> > amount of time
> > they block should be also about equal.
> >
> > However, I think that we need to take into account a couple of things.
> For
> > starters,
> > if the new methods were all reliant on one config, there is likelihood
> > that the
> > shortcomings for this approach would be similar to what we faced if we
> let
> > request.timeout.ms control all method timeouts. In comparison, adding
> > overloads
> > does not have this problem.
> >
> > If you have further thoughts, please let me know.
> >
> > Richard
> >
> >
> > On Mon, Mar 19, 2018 at 5:12 PM, Ismael Juma  wrote:
> >
> >> Hi,
> >>
> >> An option that is not currently covered in the KIP is to have a separate
> >> config max.block.ms, which is similar to the producer config with the
> >> same
> >> name. This came up during the KAFKA-2391 discussion. I think it's clear
> >> that we can't rely on request.timeout.ms, so the decision is between
> >> adding
> >> overloads or adding a new config. People seemed to be leaning towards
> the
> >> latter in KAFKA-2391, but Jason makes a good point that the overloads
> are
> >> more flexible. A couple of questions from me:
> >>
> >> 1. Do we need the additional flexibility?
> >> 2. If we do, do we need it for every blocking method?
> >>
> >> Ismael
> >>
> >> On Mon, Mar 19, 2018 at 5:03 PM, Richard Yu  >
> >> wrote:
> >>
> >> > Hi Guozhang,
> >> >
> >> > I made some clarifications to KIP-266, namely:
> >> > 1. Stated more specifically that commitSync will accept user input.
> >> > 2. fetchCommittedOffsets(): Made its role in blocking more clear to
> the
> >> > reader.
> >> > 3. Sketched what would happen when time limit is exceeded.
> >> >
> >> > These changes should make the KIP easier to understand.
> >> >
> >> > Cheers,
> >> > Richard
> >> >
> >> > On Mon, Mar 19, 2018 at 9:33 AM, Guozhang Wang 
> >> wrote:
> >> >
> >> > > Hi Richard,
> >> > >
> >> > > I made a pass over the KIP again, some more clarifications /
> comments:
> >> > >
> >> > > 1. seek() call itself is not blocking, only the following poll()
> call
> >> may
> >> > > be blocking as the actually metadata rq will happen.
> >> > >
> >> > > 2. I saw you did not include Consumer.partitionFor(),
> >> > > Consumer.OffsetAndTimestamp() and Consumer.listTopics() in your KIP.
> >> > After
> >> > > a second thought, I think this may be a better idea to not tackle
> >> them in
> >> > > the same KIP, and probably we should consider whether we would
> change
> >> the
> >> > > behavior or not in another discussion. So I agree to not include
> them.
> >> > >
> >> > > 3. In your wiki you mentioned "Another change shall be made to
> >> > > KafkaConsumer#poll(), due to its call to updateFetchPositions()
> which
> >> > > blocks indefinitely." This part may a bit obscure to most readers
> >> who's
> >> > not
> >> > > familiar with the KafkaConsumer internals, could you please add more
> >> > > elaborations. More specifically, I think the root causes of the
> public
> >> > APIs
> >> > > mentioned are a bit different while the KIP's explanation sounds
> like
> >> > they
> >> > > are due to the same reason:
> >> > >
> >> > > 3.1 fetchCommittedOffsets(): this internal call will block forever
> if
> >> the
> >> > > committed offsets cannot be fetched successfully and affect
> position()
> >> > and
> >> > > committed(). We need to break out of its internal while loop.
> >> > > 3.2 position() itself will while loop when offsets cannot be
> >> retrieved in
> >> > > the underlying async call. We need to break out this while loop.
> >> > > 3.3 commitSync() passed Long.MAX_VALUE as the timeout value, we
> should
> >> > take
> >> > > the user specified timeouts when applicable.
> >> > >
> >> > >
> >> > >
> >> > > Guozhang
> >> > >
> >> > > On 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

I do have one question though: in the current KIP, throwing
TimeoutException to mark
that time limit is exceeded is applied to all new methods introduced in
this proposal.
However, how would users respond when a TimeoutException (since it is
considered
a RuntimeException)?

Thanks,
Richard



On Mon, Mar 19, 2018 at 6:10 PM, Richard Yu 
wrote:

> Hi Ismael,
>
> You have a great point. Since most of the methods in this KIP have similar
> callbacks (position() and committed() both use fetchCommittedOffsets(),
> and
> commitSync() is similar to position(), except just updating offsets), the
> amount of time
> they block should be also about equal.
>
> However, I think that we need to take into account a couple of things. For
> starters,
> if the new methods were all reliant on one config, there is likelihood
> that the
> shortcomings for this approach would be similar to what we faced if we let
> request.timeout.ms control all method timeouts. In comparison, adding
> overloads
> does not have this problem.
>
> If you have further thoughts, please let me know.
>
> Richard
>
>
> On Mon, Mar 19, 2018 at 5:12 PM, Ismael Juma  wrote:
>
>> Hi,
>>
>> An option that is not currently covered in the KIP is to have a separate
>> config max.block.ms, which is similar to the producer config with the
>> same
>> name. This came up during the KAFKA-2391 discussion. I think it's clear
>> that we can't rely on request.timeout.ms, so the decision is between
>> adding
>> overloads or adding a new config. People seemed to be leaning towards the
>> latter in KAFKA-2391, but Jason makes a good point that the overloads are
>> more flexible. A couple of questions from me:
>>
>> 1. Do we need the additional flexibility?
>> 2. If we do, do we need it for every blocking method?
>>
>> Ismael
>>
>> On Mon, Mar 19, 2018 at 5:03 PM, Richard Yu 
>> wrote:
>>
>> > Hi Guozhang,
>> >
>> > I made some clarifications to KIP-266, namely:
>> > 1. Stated more specifically that commitSync will accept user input.
>> > 2. fetchCommittedOffsets(): Made its role in blocking more clear to the
>> > reader.
>> > 3. Sketched what would happen when time limit is exceeded.
>> >
>> > These changes should make the KIP easier to understand.
>> >
>> > Cheers,
>> > Richard
>> >
>> > On Mon, Mar 19, 2018 at 9:33 AM, Guozhang Wang 
>> wrote:
>> >
>> > > Hi Richard,
>> > >
>> > > I made a pass over the KIP again, some more clarifications / comments:
>> > >
>> > > 1. seek() call itself is not blocking, only the following poll() call
>> may
>> > > be blocking as the actually metadata rq will happen.
>> > >
>> > > 2. I saw you did not include Consumer.partitionFor(),
>> > > Consumer.OffsetAndTimestamp() and Consumer.listTopics() in your KIP.
>> > After
>> > > a second thought, I think this may be a better idea to not tackle
>> them in
>> > > the same KIP, and probably we should consider whether we would change
>> the
>> > > behavior or not in another discussion. So I agree to not include them.
>> > >
>> > > 3. In your wiki you mentioned "Another change shall be made to
>> > > KafkaConsumer#poll(), due to its call to updateFetchPositions() which
>> > > blocks indefinitely." This part may a bit obscure to most readers
>> who's
>> > not
>> > > familiar with the KafkaConsumer internals, could you please add more
>> > > elaborations. More specifically, I think the root causes of the public
>> > APIs
>> > > mentioned are a bit different while the KIP's explanation sounds like
>> > they
>> > > are due to the same reason:
>> > >
>> > > 3.1 fetchCommittedOffsets(): this internal call will block forever if
>> the
>> > > committed offsets cannot be fetched successfully and affect position()
>> > and
>> > > committed(). We need to break out of its internal while loop.
>> > > 3.2 position() itself will while loop when offsets cannot be
>> retrieved in
>> > > the underlying async call. We need to break out this while loop.
>> > > 3.3 commitSync() passed Long.MAX_VALUE as the timeout value, we should
>> > take
>> > > the user specified timeouts when applicable.
>> > >
>> > >
>> > >
>> > > Guozhang
>> > >
>> > > On Sat, Mar 17, 2018 at 4:44 PM, Richard Yu <
>> yohan.richard...@gmail.com>
>> > > wrote:
>> > >
>> > > > Actually, what I said above is inaccurate. In
>> > > > testSeekAndCommitWithBrokerFailures, TestUtils.waitUntilTrue
>> blocks,
>> > not
>> > > > seek.
>> > > > My assumption is that seek did not update correctly. I will be
>> digging
>> > > > further into this.
>> > > >
>> > > >
>> > > >
>> > > > On Sat, Mar 17, 2018 at 4:16 PM, Richard Yu <
>> > yohan.richard...@gmail.com>
>> > > > wrote:
>> > > >
>> > > > > One more thing: when looking through tests, I have realized that
>> > seek()
>> > > > > methods can potentially block indefinitely. As you well know,
>> seek()
>> > is
>> > > > > called when pollOnce() or position() is active. Thus, if
>> position()
>> > > > blocks
>> > > > 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Hi Ismael,

You have a great point. Since most of the methods in this KIP have similar
callbacks (position() and committed() both use fetchCommittedOffsets(), and
commitSync() is similar to position(), except just updating offsets), the
amount of time
they block should be also about equal.

However, I think that we need to take into account a couple of things. For
starters,
if the new methods were all reliant on one config, there is likelihood that
the
shortcomings for this approach would be similar to what we faced if we let
request.timeout.ms control all method timeouts. In comparison, adding
overloads
does not have this problem.

If you have further thoughts, please let me know.

Richard


On Mon, Mar 19, 2018 at 5:12 PM, Ismael Juma  wrote:

> Hi,
>
> An option that is not currently covered in the KIP is to have a separate
> config max.block.ms, which is similar to the producer config with the same
> name. This came up during the KAFKA-2391 discussion. I think it's clear
> that we can't rely on request.timeout.ms, so the decision is between
> adding
> overloads or adding a new config. People seemed to be leaning towards the
> latter in KAFKA-2391, but Jason makes a good point that the overloads are
> more flexible. A couple of questions from me:
>
> 1. Do we need the additional flexibility?
> 2. If we do, do we need it for every blocking method?
>
> Ismael
>
> On Mon, Mar 19, 2018 at 5:03 PM, Richard Yu 
> wrote:
>
> > Hi Guozhang,
> >
> > I made some clarifications to KIP-266, namely:
> > 1. Stated more specifically that commitSync will accept user input.
> > 2. fetchCommittedOffsets(): Made its role in blocking more clear to the
> > reader.
> > 3. Sketched what would happen when time limit is exceeded.
> >
> > These changes should make the KIP easier to understand.
> >
> > Cheers,
> > Richard
> >
> > On Mon, Mar 19, 2018 at 9:33 AM, Guozhang Wang 
> wrote:
> >
> > > Hi Richard,
> > >
> > > I made a pass over the KIP again, some more clarifications / comments:
> > >
> > > 1. seek() call itself is not blocking, only the following poll() call
> may
> > > be blocking as the actually metadata rq will happen.
> > >
> > > 2. I saw you did not include Consumer.partitionFor(),
> > > Consumer.OffsetAndTimestamp() and Consumer.listTopics() in your KIP.
> > After
> > > a second thought, I think this may be a better idea to not tackle them
> in
> > > the same KIP, and probably we should consider whether we would change
> the
> > > behavior or not in another discussion. So I agree to not include them.
> > >
> > > 3. In your wiki you mentioned "Another change shall be made to
> > > KafkaConsumer#poll(), due to its call to updateFetchPositions() which
> > > blocks indefinitely." This part may a bit obscure to most readers who's
> > not
> > > familiar with the KafkaConsumer internals, could you please add more
> > > elaborations. More specifically, I think the root causes of the public
> > APIs
> > > mentioned are a bit different while the KIP's explanation sounds like
> > they
> > > are due to the same reason:
> > >
> > > 3.1 fetchCommittedOffsets(): this internal call will block forever if
> the
> > > committed offsets cannot be fetched successfully and affect position()
> > and
> > > committed(). We need to break out of its internal while loop.
> > > 3.2 position() itself will while loop when offsets cannot be retrieved
> in
> > > the underlying async call. We need to break out this while loop.
> > > 3.3 commitSync() passed Long.MAX_VALUE as the timeout value, we should
> > take
> > > the user specified timeouts when applicable.
> > >
> > >
> > >
> > > Guozhang
> > >
> > > On Sat, Mar 17, 2018 at 4:44 PM, Richard Yu <
> yohan.richard...@gmail.com>
> > > wrote:
> > >
> > > > Actually, what I said above is inaccurate. In
> > > > testSeekAndCommitWithBrokerFailures, TestUtils.waitUntilTrue blocks,
> > not
> > > > seek.
> > > > My assumption is that seek did not update correctly. I will be
> digging
> > > > further into this.
> > > >
> > > >
> > > >
> > > > On Sat, Mar 17, 2018 at 4:16 PM, Richard Yu <
> > yohan.richard...@gmail.com>
> > > > wrote:
> > > >
> > > > > One more thing: when looking through tests, I have realized that
> > seek()
> > > > > methods can potentially block indefinitely. As you well know,
> seek()
> > is
> > > > > called when pollOnce() or position() is active. Thus, if position()
> > > > blocks
> > > > > indefinitely, then so would seek(). Should bounding seek() also be
> > > > included
> > > > > in this KIP?
> > > > >
> > > > > Thanks, Richard
> > > > >
> > > > > On Sat, Mar 17, 2018 at 1:16 PM, Richard Yu <
> > > yohan.richard...@gmail.com>
> > > > > wrote:
> > > > >
> > > > >> Thanks for the advice, Jason
> > > > >>
> > > > >> I have modified KIP-266 to include the java doc for committed()
> and
> > > > other
> > > > >> blocking methods, and I also
> > > > >> mentioned poll() which will also be bounded. Let me know if there

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Ismael Juma]

Hi,

An option that is not currently covered in the KIP is to have a separate
config max.block.ms, which is similar to the producer config with the same
name. This came up during the KAFKA-2391 discussion. I think it's clear
that we can't rely on request.timeout.ms, so the decision is between adding
overloads or adding a new config. People seemed to be leaning towards the
latter in KAFKA-2391, but Jason makes a good point that the overloads are
more flexible. A couple of questions from me:

1. Do we need the additional flexibility?
2. If we do, do we need it for every blocking method?

Ismael

On Mon, Mar 19, 2018 at 5:03 PM, Richard Yu 
wrote:

> Hi Guozhang,
>
> I made some clarifications to KIP-266, namely:
> 1. Stated more specifically that commitSync will accept user input.
> 2. fetchCommittedOffsets(): Made its role in blocking more clear to the
> reader.
> 3. Sketched what would happen when time limit is exceeded.
>
> These changes should make the KIP easier to understand.
>
> Cheers,
> Richard
>
> On Mon, Mar 19, 2018 at 9:33 AM, Guozhang Wang  wrote:
>
> > Hi Richard,
> >
> > I made a pass over the KIP again, some more clarifications / comments:
> >
> > 1. seek() call itself is not blocking, only the following poll() call may
> > be blocking as the actually metadata rq will happen.
> >
> > 2. I saw you did not include Consumer.partitionFor(),
> > Consumer.OffsetAndTimestamp() and Consumer.listTopics() in your KIP.
> After
> > a second thought, I think this may be a better idea to not tackle them in
> > the same KIP, and probably we should consider whether we would change the
> > behavior or not in another discussion. So I agree to not include them.
> >
> > 3. In your wiki you mentioned "Another change shall be made to
> > KafkaConsumer#poll(), due to its call to updateFetchPositions() which
> > blocks indefinitely." This part may a bit obscure to most readers who's
> not
> > familiar with the KafkaConsumer internals, could you please add more
> > elaborations. More specifically, I think the root causes of the public
> APIs
> > mentioned are a bit different while the KIP's explanation sounds like
> they
> > are due to the same reason:
> >
> > 3.1 fetchCommittedOffsets(): this internal call will block forever if the
> > committed offsets cannot be fetched successfully and affect position()
> and
> > committed(). We need to break out of its internal while loop.
> > 3.2 position() itself will while loop when offsets cannot be retrieved in
> > the underlying async call. We need to break out this while loop.
> > 3.3 commitSync() passed Long.MAX_VALUE as the timeout value, we should
> take
> > the user specified timeouts when applicable.
> >
> >
> >
> > Guozhang
> >
> > On Sat, Mar 17, 2018 at 4:44 PM, Richard Yu 
> > wrote:
> >
> > > Actually, what I said above is inaccurate. In
> > > testSeekAndCommitWithBrokerFailures, TestUtils.waitUntilTrue blocks,
> not
> > > seek.
> > > My assumption is that seek did not update correctly. I will be digging
> > > further into this.
> > >
> > >
> > >
> > > On Sat, Mar 17, 2018 at 4:16 PM, Richard Yu <
> yohan.richard...@gmail.com>
> > > wrote:
> > >
> > > > One more thing: when looking through tests, I have realized that
> seek()
> > > > methods can potentially block indefinitely. As you well know, seek()
> is
> > > > called when pollOnce() or position() is active. Thus, if position()
> > > blocks
> > > > indefinitely, then so would seek(). Should bounding seek() also be
> > > included
> > > > in this KIP?
> > > >
> > > > Thanks, Richard
> > > >
> > > > On Sat, Mar 17, 2018 at 1:16 PM, Richard Yu <
> > yohan.richard...@gmail.com>
> > > > wrote:
> > > >
> > > >> Thanks for the advice, Jason
> > > >>
> > > >> I have modified KIP-266 to include the java doc for committed() and
> > > other
> > > >> blocking methods, and I also
> > > >> mentioned poll() which will also be bounded. Let me know if there is
> > > >> anything else. :)
> > > >>
> > > >> Sincerely, Richard
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >> On Sat, Mar 17, 2018 at 12:00 PM, Jason Gustafson <
> ja...@confluent.io
> > >
> > > >> wrote:
> > > >>
> > > >>> Hi Richard,
> > > >>>
> > > >>> Thanks for the updates. I'm really glad you picked this up. A
> couple
> > > >>> minor
> > > >>> comments:
> > > >>>
> > > >>> 1. Can you list the full set of new APIs explicitly in the KIP?
> > > >>> Currently I
> > > >>> only see the javadoc for `position()`.
> > > >>>
> > > >>> 2. We should consider adding `TimeUnit` to the new methods to avoid
> > > unit
> > > >>> confusion. I know it's inconsistent with the poll() API, but I
> think
> > it
> > > >>> was
> > > >>> probably a mistake not to include it there, so better not to double
> > > down
> > > >>> on
> > > >>> that mistake. And note that we do already have `close(long,
> > TimeUnit)`.
> > > >>>
> > > >>> Other than that, I think the current KIP seems reasonable.
> > > >>>
> > > 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Hi Guozhang,

I made some clarifications to KIP-266, namely:
1. Stated more specifically that commitSync will accept user input.
2. fetchCommittedOffsets(): Made its role in blocking more clear to the
reader.
3. Sketched what would happen when time limit is exceeded.

These changes should make the KIP easier to understand.

Cheers,
Richard

On Mon, Mar 19, 2018 at 9:33 AM, Guozhang Wang  wrote:

> Hi Richard,
>
> I made a pass over the KIP again, some more clarifications / comments:
>
> 1. seek() call itself is not blocking, only the following poll() call may
> be blocking as the actually metadata rq will happen.
>
> 2. I saw you did not include Consumer.partitionFor(),
> Consumer.OffsetAndTimestamp() and Consumer.listTopics() in your KIP. After
> a second thought, I think this may be a better idea to not tackle them in
> the same KIP, and probably we should consider whether we would change the
> behavior or not in another discussion. So I agree to not include them.
>
> 3. In your wiki you mentioned "Another change shall be made to
> KafkaConsumer#poll(), due to its call to updateFetchPositions() which
> blocks indefinitely." This part may a bit obscure to most readers who's not
> familiar with the KafkaConsumer internals, could you please add more
> elaborations. More specifically, I think the root causes of the public APIs
> mentioned are a bit different while the KIP's explanation sounds like they
> are due to the same reason:
>
> 3.1 fetchCommittedOffsets(): this internal call will block forever if the
> committed offsets cannot be fetched successfully and affect position() and
> committed(). We need to break out of its internal while loop.
> 3.2 position() itself will while loop when offsets cannot be retrieved in
> the underlying async call. We need to break out this while loop.
> 3.3 commitSync() passed Long.MAX_VALUE as the timeout value, we should take
> the user specified timeouts when applicable.
>
>
>
> Guozhang
>
> On Sat, Mar 17, 2018 at 4:44 PM, Richard Yu 
> wrote:
>
> > Actually, what I said above is inaccurate. In
> > testSeekAndCommitWithBrokerFailures, TestUtils.waitUntilTrue blocks, not
> > seek.
> > My assumption is that seek did not update correctly. I will be digging
> > further into this.
> >
> >
> >
> > On Sat, Mar 17, 2018 at 4:16 PM, Richard Yu 
> > wrote:
> >
> > > One more thing: when looking through tests, I have realized that seek()
> > > methods can potentially block indefinitely. As you well know, seek() is
> > > called when pollOnce() or position() is active. Thus, if position()
> > blocks
> > > indefinitely, then so would seek(). Should bounding seek() also be
> > included
> > > in this KIP?
> > >
> > > Thanks, Richard
> > >
> > > On Sat, Mar 17, 2018 at 1:16 PM, Richard Yu <
> yohan.richard...@gmail.com>
> > > wrote:
> > >
> > >> Thanks for the advice, Jason
> > >>
> > >> I have modified KIP-266 to include the java doc for committed() and
> > other
> > >> blocking methods, and I also
> > >> mentioned poll() which will also be bounded. Let me know if there is
> > >> anything else. :)
> > >>
> > >> Sincerely, Richard
> > >>
> > >>
> > >>
> > >>
> > >>
> > >> On Sat, Mar 17, 2018 at 12:00 PM, Jason Gustafson  >
> > >> wrote:
> > >>
> > >>> Hi Richard,
> > >>>
> > >>> Thanks for the updates. I'm really glad you picked this up. A couple
> > >>> minor
> > >>> comments:
> > >>>
> > >>> 1. Can you list the full set of new APIs explicitly in the KIP?
> > >>> Currently I
> > >>> only see the javadoc for `position()`.
> > >>>
> > >>> 2. We should consider adding `TimeUnit` to the new methods to avoid
> > unit
> > >>> confusion. I know it's inconsistent with the poll() API, but I think
> it
> > >>> was
> > >>> probably a mistake not to include it there, so better not to double
> > down
> > >>> on
> > >>> that mistake. And note that we do already have `close(long,
> TimeUnit)`.
> > >>>
> > >>> Other than that, I think the current KIP seems reasonable.
> > >>>
> > >>> Thanks,
> > >>> Jason
> > >>>
> > >>> On Wed, Mar 14, 2018 at 5:00 PM, Richard Yu <
> > yohan.richard...@gmail.com>
> > >>> wrote:
> > >>>
> > >>> > Note to all: I have included bounding commitSync() and committed()
> in
> > >>> this
> > >>> > KIP.
> > >>> >
> > >>> > On Sun, Mar 11, 2018 at 5:05 PM, Richard Yu <
> > >>> yohan.richard...@gmail.com>
> > >>> > wrote:
> > >>> >
> > >>> > > Hi all,
> > >>> > >
> > >>> > > I updated the KIP where overloading position() is now the favored
> > >>> > approach.
> > >>> > > Bounding position() using requestTimeoutMs has been listed as
> > >>> rejected.
> > >>> > >
> > >>> > > Any thoughts?
> > >>> > >
> > >>> > > On Tue, Mar 6, 2018 at 6:00 PM, Guozhang Wang <
> wangg...@gmail.com>
> > >>> > wrote:
> > >>> > >
> > >>> > >> I agree that adding the overloads is most flexible. But going
> for
> > >>> that
> > >>> > >> direction we'd do that for all the blocking call that I've
> listed
> 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Guozhang Wang]

Hi Richard,

I made a pass over the KIP again, some more clarifications / comments:

1. seek() call itself is not blocking, only the following poll() call may
be blocking as the actually metadata rq will happen.

2. I saw you did not include Consumer.partitionFor(),
Consumer.OffsetAndTimestamp() and Consumer.listTopics() in your KIP. After
a second thought, I think this may be a better idea to not tackle them in
the same KIP, and probably we should consider whether we would change the
behavior or not in another discussion. So I agree to not include them.

3. In your wiki you mentioned "Another change shall be made to
KafkaConsumer#poll(), due to its call to updateFetchPositions() which
blocks indefinitely." This part may a bit obscure to most readers who's not
familiar with the KafkaConsumer internals, could you please add more
elaborations. More specifically, I think the root causes of the public APIs
mentioned are a bit different while the KIP's explanation sounds like they
are due to the same reason:

3.1 fetchCommittedOffsets(): this internal call will block forever if the
committed offsets cannot be fetched successfully and affect position() and
committed(). We need to break out of its internal while loop.
3.2 position() itself will while loop when offsets cannot be retrieved in
the underlying async call. We need to break out this while loop.
3.3 commitSync() passed Long.MAX_VALUE as the timeout value, we should take
the user specified timeouts when applicable.



Guozhang

On Sat, Mar 17, 2018 at 4:44 PM, Richard Yu 
wrote:

> Actually, what I said above is inaccurate. In
> testSeekAndCommitWithBrokerFailures, TestUtils.waitUntilTrue blocks, not
> seek.
> My assumption is that seek did not update correctly. I will be digging
> further into this.
>
>
>
> On Sat, Mar 17, 2018 at 4:16 PM, Richard Yu 
> wrote:
>
> > One more thing: when looking through tests, I have realized that seek()
> > methods can potentially block indefinitely. As you well know, seek() is
> > called when pollOnce() or position() is active. Thus, if position()
> blocks
> > indefinitely, then so would seek(). Should bounding seek() also be
> included
> > in this KIP?
> >
> > Thanks, Richard
> >
> > On Sat, Mar 17, 2018 at 1:16 PM, Richard Yu 
> > wrote:
> >
> >> Thanks for the advice, Jason
> >>
> >> I have modified KIP-266 to include the java doc for committed() and
> other
> >> blocking methods, and I also
> >> mentioned poll() which will also be bounded. Let me know if there is
> >> anything else. :)
> >>
> >> Sincerely, Richard
> >>
> >>
> >>
> >>
> >>
> >> On Sat, Mar 17, 2018 at 12:00 PM, Jason Gustafson 
> >> wrote:
> >>
> >>> Hi Richard,
> >>>
> >>> Thanks for the updates. I'm really glad you picked this up. A couple
> >>> minor
> >>> comments:
> >>>
> >>> 1. Can you list the full set of new APIs explicitly in the KIP?
> >>> Currently I
> >>> only see the javadoc for `position()`.
> >>>
> >>> 2. We should consider adding `TimeUnit` to the new methods to avoid
> unit
> >>> confusion. I know it's inconsistent with the poll() API, but I think it
> >>> was
> >>> probably a mistake not to include it there, so better not to double
> down
> >>> on
> >>> that mistake. And note that we do already have `close(long, TimeUnit)`.
> >>>
> >>> Other than that, I think the current KIP seems reasonable.
> >>>
> >>> Thanks,
> >>> Jason
> >>>
> >>> On Wed, Mar 14, 2018 at 5:00 PM, Richard Yu <
> yohan.richard...@gmail.com>
> >>> wrote:
> >>>
> >>> > Note to all: I have included bounding commitSync() and committed() in
> >>> this
> >>> > KIP.
> >>> >
> >>> > On Sun, Mar 11, 2018 at 5:05 PM, Richard Yu <
> >>> yohan.richard...@gmail.com>
> >>> > wrote:
> >>> >
> >>> > > Hi all,
> >>> > >
> >>> > > I updated the KIP where overloading position() is now the favored
> >>> > approach.
> >>> > > Bounding position() using requestTimeoutMs has been listed as
> >>> rejected.
> >>> > >
> >>> > > Any thoughts?
> >>> > >
> >>> > > On Tue, Mar 6, 2018 at 6:00 PM, Guozhang Wang 
> >>> > wrote:
> >>> > >
> >>> > >> I agree that adding the overloads is most flexible. But going for
> >>> that
> >>> > >> direction we'd do that for all the blocking call that I've listed
> >>> above,
> >>> > >> with this timeout value covering the end-to-end waiting time.
> >>> > >>
> >>> > >>
> >>> > >> Guozhang
> >>> > >>
> >>> > >> On Tue, Mar 6, 2018 at 10:02 AM, Ted Yu 
> >>> wrote:
> >>> > >>
> >>> > >> > bq. The most flexible option is to add overloads to the consumer
> >>> > >> >
> >>> > >> > This option is flexible.
> >>> > >> >
> >>> > >> > Looking at the tail of SPARK-18057, Spark dev voiced the same
> >>> choice.
> >>> > >> >
> >>> > >> > +1 for adding overload with timeout parameter.
> >>> > >> >
> >>> > >> > Cheers
> >>> > >> >
> >>> > >> > On Mon, Mar 5, 2018 at 2:42 PM, Jason Gustafson <
> >>> ja...@confluent.io>
> >>> > >> 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Actually, what I said above is inaccurate. In
testSeekAndCommitWithBrokerFailures, TestUtils.waitUntilTrue blocks, not
seek.
My assumption is that seek did not update correctly. I will be digging
further into this.



On Sat, Mar 17, 2018 at 4:16 PM, Richard Yu 
wrote:

> One more thing: when looking through tests, I have realized that seek()
> methods can potentially block indefinitely. As you well know, seek() is
> called when pollOnce() or position() is active. Thus, if position() blocks
> indefinitely, then so would seek(). Should bounding seek() also be included
> in this KIP?
>
> Thanks, Richard
>
> On Sat, Mar 17, 2018 at 1:16 PM, Richard Yu 
> wrote:
>
>> Thanks for the advice, Jason
>>
>> I have modified KIP-266 to include the java doc for committed() and other
>> blocking methods, and I also
>> mentioned poll() which will also be bounded. Let me know if there is
>> anything else. :)
>>
>> Sincerely, Richard
>>
>>
>>
>>
>>
>> On Sat, Mar 17, 2018 at 12:00 PM, Jason Gustafson 
>> wrote:
>>
>>> Hi Richard,
>>>
>>> Thanks for the updates. I'm really glad you picked this up. A couple
>>> minor
>>> comments:
>>>
>>> 1. Can you list the full set of new APIs explicitly in the KIP?
>>> Currently I
>>> only see the javadoc for `position()`.
>>>
>>> 2. We should consider adding `TimeUnit` to the new methods to avoid unit
>>> confusion. I know it's inconsistent with the poll() API, but I think it
>>> was
>>> probably a mistake not to include it there, so better not to double down
>>> on
>>> that mistake. And note that we do already have `close(long, TimeUnit)`.
>>>
>>> Other than that, I think the current KIP seems reasonable.
>>>
>>> Thanks,
>>> Jason
>>>
>>> On Wed, Mar 14, 2018 at 5:00 PM, Richard Yu 
>>> wrote:
>>>
>>> > Note to all: I have included bounding commitSync() and committed() in
>>> this
>>> > KIP.
>>> >
>>> > On Sun, Mar 11, 2018 at 5:05 PM, Richard Yu <
>>> yohan.richard...@gmail.com>
>>> > wrote:
>>> >
>>> > > Hi all,
>>> > >
>>> > > I updated the KIP where overloading position() is now the favored
>>> > approach.
>>> > > Bounding position() using requestTimeoutMs has been listed as
>>> rejected.
>>> > >
>>> > > Any thoughts?
>>> > >
>>> > > On Tue, Mar 6, 2018 at 6:00 PM, Guozhang Wang 
>>> > wrote:
>>> > >
>>> > >> I agree that adding the overloads is most flexible. But going for
>>> that
>>> > >> direction we'd do that for all the blocking call that I've listed
>>> above,
>>> > >> with this timeout value covering the end-to-end waiting time.
>>> > >>
>>> > >>
>>> > >> Guozhang
>>> > >>
>>> > >> On Tue, Mar 6, 2018 at 10:02 AM, Ted Yu 
>>> wrote:
>>> > >>
>>> > >> > bq. The most flexible option is to add overloads to the consumer
>>> > >> >
>>> > >> > This option is flexible.
>>> > >> >
>>> > >> > Looking at the tail of SPARK-18057, Spark dev voiced the same
>>> choice.
>>> > >> >
>>> > >> > +1 for adding overload with timeout parameter.
>>> > >> >
>>> > >> > Cheers
>>> > >> >
>>> > >> > On Mon, Mar 5, 2018 at 2:42 PM, Jason Gustafson <
>>> ja...@confluent.io>
>>> > >> > wrote:
>>> > >> >
>>> > >> > > @Guozhang I probably have suggested all options at some point or
>>> > >> another,
>>> > >> > > including most recently, the current KIP! I was thinking that
>>> > >> practically
>>> > >> > > speaking, the request timeout defines how long the user is
>>> willing
>>> > to
>>> > >> > wait
>>> > >> > > for a response. The consumer doesn't really have a complex send
>>> > >> process
>>> > >> > > like the producer for any of these APIs, so I wasn't sure how
>>> much
>>> > >> > benefit
>>> > >> > > there would be from having more granular control over timeouts
>>> (in
>>> > the
>>> > >> > end,
>>> > >> > > KIP-91 just adds a single timeout to control the whole send).
>>> That
>>> > >> said,
>>> > >> > it
>>> > >> > > might indeed be better to avoid overloading the config as you
>>> > suggest
>>> > >> > since
>>> > >> > > at least it avoids inconsistency with the producer's usage.
>>> > >> > >
>>> > >> > > The most flexible option is to add overloads to the consumer so
>>> that
>>> > >> > users
>>> > >> > > can pass the timeout directly. I'm not sure if that is more or
>>> less
>>> > >> > > annoying than a new config, but I've found config timeouts a
>>> little
>>> > >> > > constraining in practice. For example, I could imagine users
>>> wanting
>>> > >> to
>>> > >> > > wait longer for an offset commit operation than a position
>>> lookup;
>>> > if
>>> > >> the
>>> > >> > > latter isn't timely, users can just pause the partition and
>>> continue
>>> > >> > > fetching on others. If you cannot commit offsets, however, it
>>> might
>>> > be
>>> > >> > > safer for an application to wait availability of the coordinator
>>> > than
>>> > >> > > continuing.
>>> > >> > >
>>> > >> > > -Jason
>>> > >> > >
>>> > >> > > On Sun, Mar 4, 2018 at 10:14 PM, Guozhang Wang <

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

One more thing: when looking through tests, I have realized that seek()
methods can potentially block indefinitely. As you well know, seek() is
called when pollOnce() or position() is active. Thus, if position() blocks
indefinitely, then so would seek(). Should bounding seek() also be included
in this KIP?

Thanks, Richard

On Sat, Mar 17, 2018 at 1:16 PM, Richard Yu 
wrote:

> Thanks for the advice, Jason
>
> I have modified KIP-266 to include the java doc for committed() and other
> blocking methods, and I also
> mentioned poll() which will also be bounded. Let me know if there is
> anything else. :)
>
> Sincerely, Richard
>
>
>
>
>
> On Sat, Mar 17, 2018 at 12:00 PM, Jason Gustafson 
> wrote:
>
>> Hi Richard,
>>
>> Thanks for the updates. I'm really glad you picked this up. A couple minor
>> comments:
>>
>> 1. Can you list the full set of new APIs explicitly in the KIP? Currently
>> I
>> only see the javadoc for `position()`.
>>
>> 2. We should consider adding `TimeUnit` to the new methods to avoid unit
>> confusion. I know it's inconsistent with the poll() API, but I think it
>> was
>> probably a mistake not to include it there, so better not to double down
>> on
>> that mistake. And note that we do already have `close(long, TimeUnit)`.
>>
>> Other than that, I think the current KIP seems reasonable.
>>
>> Thanks,
>> Jason
>>
>> On Wed, Mar 14, 2018 at 5:00 PM, Richard Yu 
>> wrote:
>>
>> > Note to all: I have included bounding commitSync() and committed() in
>> this
>> > KIP.
>> >
>> > On Sun, Mar 11, 2018 at 5:05 PM, Richard Yu > >
>> > wrote:
>> >
>> > > Hi all,
>> > >
>> > > I updated the KIP where overloading position() is now the favored
>> > approach.
>> > > Bounding position() using requestTimeoutMs has been listed as
>> rejected.
>> > >
>> > > Any thoughts?
>> > >
>> > > On Tue, Mar 6, 2018 at 6:00 PM, Guozhang Wang 
>> > wrote:
>> > >
>> > >> I agree that adding the overloads is most flexible. But going for
>> that
>> > >> direction we'd do that for all the blocking call that I've listed
>> above,
>> > >> with this timeout value covering the end-to-end waiting time.
>> > >>
>> > >>
>> > >> Guozhang
>> > >>
>> > >> On Tue, Mar 6, 2018 at 10:02 AM, Ted Yu  wrote:
>> > >>
>> > >> > bq. The most flexible option is to add overloads to the consumer
>> > >> >
>> > >> > This option is flexible.
>> > >> >
>> > >> > Looking at the tail of SPARK-18057, Spark dev voiced the same
>> choice.
>> > >> >
>> > >> > +1 for adding overload with timeout parameter.
>> > >> >
>> > >> > Cheers
>> > >> >
>> > >> > On Mon, Mar 5, 2018 at 2:42 PM, Jason Gustafson <
>> ja...@confluent.io>
>> > >> > wrote:
>> > >> >
>> > >> > > @Guozhang I probably have suggested all options at some point or
>> > >> another,
>> > >> > > including most recently, the current KIP! I was thinking that
>> > >> practically
>> > >> > > speaking, the request timeout defines how long the user is
>> willing
>> > to
>> > >> > wait
>> > >> > > for a response. The consumer doesn't really have a complex send
>> > >> process
>> > >> > > like the producer for any of these APIs, so I wasn't sure how
>> much
>> > >> > benefit
>> > >> > > there would be from having more granular control over timeouts
>> (in
>> > the
>> > >> > end,
>> > >> > > KIP-91 just adds a single timeout to control the whole send).
>> That
>> > >> said,
>> > >> > it
>> > >> > > might indeed be better to avoid overloading the config as you
>> > suggest
>> > >> > since
>> > >> > > at least it avoids inconsistency with the producer's usage.
>> > >> > >
>> > >> > > The most flexible option is to add overloads to the consumer so
>> that
>> > >> > users
>> > >> > > can pass the timeout directly. I'm not sure if that is more or
>> less
>> > >> > > annoying than a new config, but I've found config timeouts a
>> little
>> > >> > > constraining in practice. For example, I could imagine users
>> wanting
>> > >> to
>> > >> > > wait longer for an offset commit operation than a position
>> lookup;
>> > if
>> > >> the
>> > >> > > latter isn't timely, users can just pause the partition and
>> continue
>> > >> > > fetching on others. If you cannot commit offsets, however, it
>> might
>> > be
>> > >> > > safer for an application to wait availability of the coordinator
>> > than
>> > >> > > continuing.
>> > >> > >
>> > >> > > -Jason
>> > >> > >
>> > >> > > On Sun, Mar 4, 2018 at 10:14 PM, Guozhang Wang <
>> wangg...@gmail.com>
>> > >> > wrote:
>> > >> > >
>> > >> > > > Hello Richard,
>> > >> > > >
>> > >> > > > Thanks for the proposed KIP. I have a couple of general
>> comments:
>> > >> > > >
>> > >> > > > 1. I'm not sure if piggy-backing the timeout exception on the
>> > >> > > > existing requestTimeoutMs configured in "request.timeout.ms"
>> is a
>> > >> good
>> > >> > > > idea
>> > >> > > > since a) it is a general config that applies for all types of
>> > 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Thanks for the advice, Jason

I have modified KIP-266 to include the java doc for committed() and other
blocking methods, and I also
mentioned poll() which will also be bounded. Let me know if there is
anything else. :)

Sincerely, Richard





On Sat, Mar 17, 2018 at 12:00 PM, Jason Gustafson 
wrote:

> Hi Richard,
>
> Thanks for the updates. I'm really glad you picked this up. A couple minor
> comments:
>
> 1. Can you list the full set of new APIs explicitly in the KIP? Currently I
> only see the javadoc for `position()`.
>
> 2. We should consider adding `TimeUnit` to the new methods to avoid unit
> confusion. I know it's inconsistent with the poll() API, but I think it was
> probably a mistake not to include it there, so better not to double down on
> that mistake. And note that we do already have `close(long, TimeUnit)`.
>
> Other than that, I think the current KIP seems reasonable.
>
> Thanks,
> Jason
>
> On Wed, Mar 14, 2018 at 5:00 PM, Richard Yu 
> wrote:
>
> > Note to all: I have included bounding commitSync() and committed() in
> this
> > KIP.
> >
> > On Sun, Mar 11, 2018 at 5:05 PM, Richard Yu 
> > wrote:
> >
> > > Hi all,
> > >
> > > I updated the KIP where overloading position() is now the favored
> > approach.
> > > Bounding position() using requestTimeoutMs has been listed as rejected.
> > >
> > > Any thoughts?
> > >
> > > On Tue, Mar 6, 2018 at 6:00 PM, Guozhang Wang 
> > wrote:
> > >
> > >> I agree that adding the overloads is most flexible. But going for that
> > >> direction we'd do that for all the blocking call that I've listed
> above,
> > >> with this timeout value covering the end-to-end waiting time.
> > >>
> > >>
> > >> Guozhang
> > >>
> > >> On Tue, Mar 6, 2018 at 10:02 AM, Ted Yu  wrote:
> > >>
> > >> > bq. The most flexible option is to add overloads to the consumer
> > >> >
> > >> > This option is flexible.
> > >> >
> > >> > Looking at the tail of SPARK-18057, Spark dev voiced the same
> choice.
> > >> >
> > >> > +1 for adding overload with timeout parameter.
> > >> >
> > >> > Cheers
> > >> >
> > >> > On Mon, Mar 5, 2018 at 2:42 PM, Jason Gustafson  >
> > >> > wrote:
> > >> >
> > >> > > @Guozhang I probably have suggested all options at some point or
> > >> another,
> > >> > > including most recently, the current KIP! I was thinking that
> > >> practically
> > >> > > speaking, the request timeout defines how long the user is willing
> > to
> > >> > wait
> > >> > > for a response. The consumer doesn't really have a complex send
> > >> process
> > >> > > like the producer for any of these APIs, so I wasn't sure how much
> > >> > benefit
> > >> > > there would be from having more granular control over timeouts (in
> > the
> > >> > end,
> > >> > > KIP-91 just adds a single timeout to control the whole send). That
> > >> said,
> > >> > it
> > >> > > might indeed be better to avoid overloading the config as you
> > suggest
> > >> > since
> > >> > > at least it avoids inconsistency with the producer's usage.
> > >> > >
> > >> > > The most flexible option is to add overloads to the consumer so
> that
> > >> > users
> > >> > > can pass the timeout directly. I'm not sure if that is more or
> less
> > >> > > annoying than a new config, but I've found config timeouts a
> little
> > >> > > constraining in practice. For example, I could imagine users
> wanting
> > >> to
> > >> > > wait longer for an offset commit operation than a position lookup;
> > if
> > >> the
> > >> > > latter isn't timely, users can just pause the partition and
> continue
> > >> > > fetching on others. If you cannot commit offsets, however, it
> might
> > be
> > >> > > safer for an application to wait availability of the coordinator
> > than
> > >> > > continuing.
> > >> > >
> > >> > > -Jason
> > >> > >
> > >> > > On Sun, Mar 4, 2018 at 10:14 PM, Guozhang Wang <
> wangg...@gmail.com>
> > >> > wrote:
> > >> > >
> > >> > > > Hello Richard,
> > >> > > >
> > >> > > > Thanks for the proposed KIP. I have a couple of general
> comments:
> > >> > > >
> > >> > > > 1. I'm not sure if piggy-backing the timeout exception on the
> > >> > > > existing requestTimeoutMs configured in "request.timeout.ms"
> is a
> > >> good
> > >> > > > idea
> > >> > > > since a) it is a general config that applies for all types of
> > >> requests,
> > >> > > and
> > >> > > > 2) using it to cover all the phases of an API call, including
> > >> network
> > >> > > round
> > >> > > > trip and potential metadata refresh is shown to not be a good
> > idea,
> > >> as
> > >> > > > illustrated in KIP-91:
> > >> > > >
> > >> > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-
> > >> > > > 91+Provide+Intuitive+User+Timeouts+in+The+Producer
> > >> > > >
> > >> > > > In fact, I think in KAFKA-4879 which is aimed for the same issue
> > as
> > >> > > > KAFKA-6608,
> > >> > > > Jason has suggested we use a new config for 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Jason Gustafson]

Hi Richard,

Thanks for the updates. I'm really glad you picked this up. A couple minor
comments:

1. Can you list the full set of new APIs explicitly in the KIP? Currently I
only see the javadoc for `position()`.

2. We should consider adding `TimeUnit` to the new methods to avoid unit
confusion. I know it's inconsistent with the poll() API, but I think it was
probably a mistake not to include it there, so better not to double down on
that mistake. And note that we do already have `close(long, TimeUnit)`.

Other than that, I think the current KIP seems reasonable.

Thanks,
Jason

On Wed, Mar 14, 2018 at 5:00 PM, Richard Yu 
wrote:

> Note to all: I have included bounding commitSync() and committed() in this
> KIP.
>
> On Sun, Mar 11, 2018 at 5:05 PM, Richard Yu 
> wrote:
>
> > Hi all,
> >
> > I updated the KIP where overloading position() is now the favored
> approach.
> > Bounding position() using requestTimeoutMs has been listed as rejected.
> >
> > Any thoughts?
> >
> > On Tue, Mar 6, 2018 at 6:00 PM, Guozhang Wang 
> wrote:
> >
> >> I agree that adding the overloads is most flexible. But going for that
> >> direction we'd do that for all the blocking call that I've listed above,
> >> with this timeout value covering the end-to-end waiting time.
> >>
> >>
> >> Guozhang
> >>
> >> On Tue, Mar 6, 2018 at 10:02 AM, Ted Yu  wrote:
> >>
> >> > bq. The most flexible option is to add overloads to the consumer
> >> >
> >> > This option is flexible.
> >> >
> >> > Looking at the tail of SPARK-18057, Spark dev voiced the same choice.
> >> >
> >> > +1 for adding overload with timeout parameter.
> >> >
> >> > Cheers
> >> >
> >> > On Mon, Mar 5, 2018 at 2:42 PM, Jason Gustafson 
> >> > wrote:
> >> >
> >> > > @Guozhang I probably have suggested all options at some point or
> >> another,
> >> > > including most recently, the current KIP! I was thinking that
> >> practically
> >> > > speaking, the request timeout defines how long the user is willing
> to
> >> > wait
> >> > > for a response. The consumer doesn't really have a complex send
> >> process
> >> > > like the producer for any of these APIs, so I wasn't sure how much
> >> > benefit
> >> > > there would be from having more granular control over timeouts (in
> the
> >> > end,
> >> > > KIP-91 just adds a single timeout to control the whole send). That
> >> said,
> >> > it
> >> > > might indeed be better to avoid overloading the config as you
> suggest
> >> > since
> >> > > at least it avoids inconsistency with the producer's usage.
> >> > >
> >> > > The most flexible option is to add overloads to the consumer so that
> >> > users
> >> > > can pass the timeout directly. I'm not sure if that is more or less
> >> > > annoying than a new config, but I've found config timeouts a little
> >> > > constraining in practice. For example, I could imagine users wanting
> >> to
> >> > > wait longer for an offset commit operation than a position lookup;
> if
> >> the
> >> > > latter isn't timely, users can just pause the partition and continue
> >> > > fetching on others. If you cannot commit offsets, however, it might
> be
> >> > > safer for an application to wait availability of the coordinator
> than
> >> > > continuing.
> >> > >
> >> > > -Jason
> >> > >
> >> > > On Sun, Mar 4, 2018 at 10:14 PM, Guozhang Wang 
> >> > wrote:
> >> > >
> >> > > > Hello Richard,
> >> > > >
> >> > > > Thanks for the proposed KIP. I have a couple of general comments:
> >> > > >
> >> > > > 1. I'm not sure if piggy-backing the timeout exception on the
> >> > > > existing requestTimeoutMs configured in "request.timeout.ms" is a
> >> good
> >> > > > idea
> >> > > > since a) it is a general config that applies for all types of
> >> requests,
> >> > > and
> >> > > > 2) using it to cover all the phases of an API call, including
> >> network
> >> > > round
> >> > > > trip and potential metadata refresh is shown to not be a good
> idea,
> >> as
> >> > > > illustrated in KIP-91:
> >> > > >
> >> > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-
> >> > > > 91+Provide+Intuitive+User+Timeouts+in+The+Producer
> >> > > >
> >> > > > In fact, I think in KAFKA-4879 which is aimed for the same issue
> as
> >> > > > KAFKA-6608,
> >> > > > Jason has suggested we use a new config for the API. Maybe this
> >> would
> >> > be
> >> > > a
> >> > > > more intuitive manner than reusing the request.timeout.ms config.
> >> > > >
> >> > > >
> >> > > > 2. Besides the Consumer.position() call, there are a couple of
> more
> >> > > > blocking calls today that could result in infinite blocking:
> >> > > > Consumer.commitSync() and Consumer.committed(), should they be
> >> > considered
> >> > > > in this KIP as well?
> >> > > >
> >> > > > 3. There are a few other APIs that are today relying on
> >> > > request.timeout.ms
> >> > > > already for breaking the infinite blocking, namely
> >> > 

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Note to all: I have included bounding commitSync() and committed() in this
KIP.

On Sun, Mar 11, 2018 at 5:05 PM, Richard Yu 
wrote:

> Hi all,
>
> I updated the KIP where overloading position() is now the favored approach.
> Bounding position() using requestTimeoutMs has been listed as rejected.
>
> Any thoughts?
>
> On Tue, Mar 6, 2018 at 6:00 PM, Guozhang Wang  wrote:
>
>> I agree that adding the overloads is most flexible. But going for that
>> direction we'd do that for all the blocking call that I've listed above,
>> with this timeout value covering the end-to-end waiting time.
>>
>>
>> Guozhang
>>
>> On Tue, Mar 6, 2018 at 10:02 AM, Ted Yu  wrote:
>>
>> > bq. The most flexible option is to add overloads to the consumer
>> >
>> > This option is flexible.
>> >
>> > Looking at the tail of SPARK-18057, Spark dev voiced the same choice.
>> >
>> > +1 for adding overload with timeout parameter.
>> >
>> > Cheers
>> >
>> > On Mon, Mar 5, 2018 at 2:42 PM, Jason Gustafson 
>> > wrote:
>> >
>> > > @Guozhang I probably have suggested all options at some point or
>> another,
>> > > including most recently, the current KIP! I was thinking that
>> practically
>> > > speaking, the request timeout defines how long the user is willing to
>> > wait
>> > > for a response. The consumer doesn't really have a complex send
>> process
>> > > like the producer for any of these APIs, so I wasn't sure how much
>> > benefit
>> > > there would be from having more granular control over timeouts (in the
>> > end,
>> > > KIP-91 just adds a single timeout to control the whole send). That
>> said,
>> > it
>> > > might indeed be better to avoid overloading the config as you suggest
>> > since
>> > > at least it avoids inconsistency with the producer's usage.
>> > >
>> > > The most flexible option is to add overloads to the consumer so that
>> > users
>> > > can pass the timeout directly. I'm not sure if that is more or less
>> > > annoying than a new config, but I've found config timeouts a little
>> > > constraining in practice. For example, I could imagine users wanting
>> to
>> > > wait longer for an offset commit operation than a position lookup; if
>> the
>> > > latter isn't timely, users can just pause the partition and continue
>> > > fetching on others. If you cannot commit offsets, however, it might be
>> > > safer for an application to wait availability of the coordinator than
>> > > continuing.
>> > >
>> > > -Jason
>> > >
>> > > On Sun, Mar 4, 2018 at 10:14 PM, Guozhang Wang 
>> > wrote:
>> > >
>> > > > Hello Richard,
>> > > >
>> > > > Thanks for the proposed KIP. I have a couple of general comments:
>> > > >
>> > > > 1. I'm not sure if piggy-backing the timeout exception on the
>> > > > existing requestTimeoutMs configured in "request.timeout.ms" is a
>> good
>> > > > idea
>> > > > since a) it is a general config that applies for all types of
>> requests,
>> > > and
>> > > > 2) using it to cover all the phases of an API call, including
>> network
>> > > round
>> > > > trip and potential metadata refresh is shown to not be a good idea,
>> as
>> > > > illustrated in KIP-91:
>> > > >
>> > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-
>> > > > 91+Provide+Intuitive+User+Timeouts+in+The+Producer
>> > > >
>> > > > In fact, I think in KAFKA-4879 which is aimed for the same issue as
>> > > > KAFKA-6608,
>> > > > Jason has suggested we use a new config for the API. Maybe this
>> would
>> > be
>> > > a
>> > > > more intuitive manner than reusing the request.timeout.ms config.
>> > > >
>> > > >
>> > > > 2. Besides the Consumer.position() call, there are a couple of more
>> > > > blocking calls today that could result in infinite blocking:
>> > > > Consumer.commitSync() and Consumer.committed(), should they be
>> > considered
>> > > > in this KIP as well?
>> > > >
>> > > > 3. There are a few other APIs that are today relying on
>> > > request.timeout.ms
>> > > > already for breaking the infinite blocking, namely
>> > > Consumer.partitionFor(),
>> > > > Consumer.OffsetAndTimestamp() and Consumer.listTopics(), if we are
>> > making
>> > > > the other blocking calls to be relying a new config as suggested in
>> 1)
>> > > > above, should we also change the semantics of these API functions
>> for
>> > > > consistency?
>> > > >
>> > > >
>> > > > Guozhang
>> > > >
>> > > >
>> > > >
>> > > >
>> > > > On Sun, Mar 4, 2018 at 11:13 AM, Richard Yu <
>> > yohan.richard...@gmail.com>
>> > > > wrote:
>> > > >
>> > > > > Hi all,
>> > > > >
>> > > > > I would like to discuss a potential change which would be made to
>> > > > > KafkaConsumer:
>> > > > > https://cwiki.apache.org/confluence/pages/viewpage.
>> > > > action?pageId=75974886
>> > > > >
>> > > > > Thanks,
>> > > > > Richard Yu
>> > > > >
>> > > >
>> > > >
>> > > >
>> > > > --
>> > > > -- Guozhang
>> > > >
>> > >
>> >
>>
>>
>>
>> --
>> -- Guozhang
>>
>
>

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Hi all,

I updated the KIP where overloading position() is now the favored approach.
Bounding position() using requestTimeoutMs has been listed as rejected.

Any thoughts?

On Tue, Mar 6, 2018 at 6:00 PM, Guozhang Wang  wrote:

> I agree that adding the overloads is most flexible. But going for that
> direction we'd do that for all the blocking call that I've listed above,
> with this timeout value covering the end-to-end waiting time.
>
>
> Guozhang
>
> On Tue, Mar 6, 2018 at 10:02 AM, Ted Yu  wrote:
>
> > bq. The most flexible option is to add overloads to the consumer
> >
> > This option is flexible.
> >
> > Looking at the tail of SPARK-18057, Spark dev voiced the same choice.
> >
> > +1 for adding overload with timeout parameter.
> >
> > Cheers
> >
> > On Mon, Mar 5, 2018 at 2:42 PM, Jason Gustafson 
> > wrote:
> >
> > > @Guozhang I probably have suggested all options at some point or
> another,
> > > including most recently, the current KIP! I was thinking that
> practically
> > > speaking, the request timeout defines how long the user is willing to
> > wait
> > > for a response. The consumer doesn't really have a complex send process
> > > like the producer for any of these APIs, so I wasn't sure how much
> > benefit
> > > there would be from having more granular control over timeouts (in the
> > end,
> > > KIP-91 just adds a single timeout to control the whole send). That
> said,
> > it
> > > might indeed be better to avoid overloading the config as you suggest
> > since
> > > at least it avoids inconsistency with the producer's usage.
> > >
> > > The most flexible option is to add overloads to the consumer so that
> > users
> > > can pass the timeout directly. I'm not sure if that is more or less
> > > annoying than a new config, but I've found config timeouts a little
> > > constraining in practice. For example, I could imagine users wanting to
> > > wait longer for an offset commit operation than a position lookup; if
> the
> > > latter isn't timely, users can just pause the partition and continue
> > > fetching on others. If you cannot commit offsets, however, it might be
> > > safer for an application to wait availability of the coordinator than
> > > continuing.
> > >
> > > -Jason
> > >
> > > On Sun, Mar 4, 2018 at 10:14 PM, Guozhang Wang 
> > wrote:
> > >
> > > > Hello Richard,
> > > >
> > > > Thanks for the proposed KIP. I have a couple of general comments:
> > > >
> > > > 1. I'm not sure if piggy-backing the timeout exception on the
> > > > existing requestTimeoutMs configured in "request.timeout.ms" is a
> good
> > > > idea
> > > > since a) it is a general config that applies for all types of
> requests,
> > > and
> > > > 2) using it to cover all the phases of an API call, including network
> > > round
> > > > trip and potential metadata refresh is shown to not be a good idea,
> as
> > > > illustrated in KIP-91:
> > > >
> > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-
> > > > 91+Provide+Intuitive+User+Timeouts+in+The+Producer
> > > >
> > > > In fact, I think in KAFKA-4879 which is aimed for the same issue as
> > > > KAFKA-6608,
> > > > Jason has suggested we use a new config for the API. Maybe this would
> > be
> > > a
> > > > more intuitive manner than reusing the request.timeout.ms config.
> > > >
> > > >
> > > > 2. Besides the Consumer.position() call, there are a couple of more
> > > > blocking calls today that could result in infinite blocking:
> > > > Consumer.commitSync() and Consumer.committed(), should they be
> > considered
> > > > in this KIP as well?
> > > >
> > > > 3. There are a few other APIs that are today relying on
> > > request.timeout.ms
> > > > already for breaking the infinite blocking, namely
> > > Consumer.partitionFor(),
> > > > Consumer.OffsetAndTimestamp() and Consumer.listTopics(), if we are
> > making
> > > > the other blocking calls to be relying a new config as suggested in
> 1)
> > > > above, should we also change the semantics of these API functions for
> > > > consistency?
> > > >
> > > >
> > > > Guozhang
> > > >
> > > >
> > > >
> > > >
> > > > On Sun, Mar 4, 2018 at 11:13 AM, Richard Yu <
> > yohan.richard...@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi all,
> > > > >
> > > > > I would like to discuss a potential change which would be made to
> > > > > KafkaConsumer:
> > > > > https://cwiki.apache.org/confluence/pages/viewpage.
> > > > action?pageId=75974886
> > > > >
> > > > > Thanks,
> > > > > Richard Yu
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > -- Guozhang
> > > >
> > >
> >
>
>
>
> --
> -- Guozhang
>

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Guozhang Wang]

I agree that adding the overloads is most flexible. But going for that
direction we'd do that for all the blocking call that I've listed above,
with this timeout value covering the end-to-end waiting time.


Guozhang

On Tue, Mar 6, 2018 at 10:02 AM, Ted Yu  wrote:

> bq. The most flexible option is to add overloads to the consumer
>
> This option is flexible.
>
> Looking at the tail of SPARK-18057, Spark dev voiced the same choice.
>
> +1 for adding overload with timeout parameter.
>
> Cheers
>
> On Mon, Mar 5, 2018 at 2:42 PM, Jason Gustafson 
> wrote:
>
> > @Guozhang I probably have suggested all options at some point or another,
> > including most recently, the current KIP! I was thinking that practically
> > speaking, the request timeout defines how long the user is willing to
> wait
> > for a response. The consumer doesn't really have a complex send process
> > like the producer for any of these APIs, so I wasn't sure how much
> benefit
> > there would be from having more granular control over timeouts (in the
> end,
> > KIP-91 just adds a single timeout to control the whole send). That said,
> it
> > might indeed be better to avoid overloading the config as you suggest
> since
> > at least it avoids inconsistency with the producer's usage.
> >
> > The most flexible option is to add overloads to the consumer so that
> users
> > can pass the timeout directly. I'm not sure if that is more or less
> > annoying than a new config, but I've found config timeouts a little
> > constraining in practice. For example, I could imagine users wanting to
> > wait longer for an offset commit operation than a position lookup; if the
> > latter isn't timely, users can just pause the partition and continue
> > fetching on others. If you cannot commit offsets, however, it might be
> > safer for an application to wait availability of the coordinator than
> > continuing.
> >
> > -Jason
> >
> > On Sun, Mar 4, 2018 at 10:14 PM, Guozhang Wang 
> wrote:
> >
> > > Hello Richard,
> > >
> > > Thanks for the proposed KIP. I have a couple of general comments:
> > >
> > > 1. I'm not sure if piggy-backing the timeout exception on the
> > > existing requestTimeoutMs configured in "request.timeout.ms" is a good
> > > idea
> > > since a) it is a general config that applies for all types of requests,
> > and
> > > 2) using it to cover all the phases of an API call, including network
> > round
> > > trip and potential metadata refresh is shown to not be a good idea, as
> > > illustrated in KIP-91:
> > >
> > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-
> > > 91+Provide+Intuitive+User+Timeouts+in+The+Producer
> > >
> > > In fact, I think in KAFKA-4879 which is aimed for the same issue as
> > > KAFKA-6608,
> > > Jason has suggested we use a new config for the API. Maybe this would
> be
> > a
> > > more intuitive manner than reusing the request.timeout.ms config.
> > >
> > >
> > > 2. Besides the Consumer.position() call, there are a couple of more
> > > blocking calls today that could result in infinite blocking:
> > > Consumer.commitSync() and Consumer.committed(), should they be
> considered
> > > in this KIP as well?
> > >
> > > 3. There are a few other APIs that are today relying on
> > request.timeout.ms
> > > already for breaking the infinite blocking, namely
> > Consumer.partitionFor(),
> > > Consumer.OffsetAndTimestamp() and Consumer.listTopics(), if we are
> making
> > > the other blocking calls to be relying a new config as suggested in 1)
> > > above, should we also change the semantics of these API functions for
> > > consistency?
> > >
> > >
> > > Guozhang
> > >
> > >
> > >
> > >
> > > On Sun, Mar 4, 2018 at 11:13 AM, Richard Yu <
> yohan.richard...@gmail.com>
> > > wrote:
> > >
> > > > Hi all,
> > > >
> > > > I would like to discuss a potential change which would be made to
> > > > KafkaConsumer:
> > > > https://cwiki.apache.org/confluence/pages/viewpage.
> > > action?pageId=75974886
> > > >
> > > > Thanks,
> > > > Richard Yu
> > > >
> > >
> > >
> > >
> > > --
> > > -- Guozhang
> > >
> >
>



-- 
-- Guozhang

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Ted Yu]

bq. The most flexible option is to add overloads to the consumer

This option is flexible.

Looking at the tail of SPARK-18057, Spark dev voiced the same choice.

+1 for adding overload with timeout parameter.

Cheers

On Mon, Mar 5, 2018 at 2:42 PM, Jason Gustafson  wrote:

> @Guozhang I probably have suggested all options at some point or another,
> including most recently, the current KIP! I was thinking that practically
> speaking, the request timeout defines how long the user is willing to wait
> for a response. The consumer doesn't really have a complex send process
> like the producer for any of these APIs, so I wasn't sure how much benefit
> there would be from having more granular control over timeouts (in the end,
> KIP-91 just adds a single timeout to control the whole send). That said, it
> might indeed be better to avoid overloading the config as you suggest since
> at least it avoids inconsistency with the producer's usage.
>
> The most flexible option is to add overloads to the consumer so that users
> can pass the timeout directly. I'm not sure if that is more or less
> annoying than a new config, but I've found config timeouts a little
> constraining in practice. For example, I could imagine users wanting to
> wait longer for an offset commit operation than a position lookup; if the
> latter isn't timely, users can just pause the partition and continue
> fetching on others. If you cannot commit offsets, however, it might be
> safer for an application to wait availability of the coordinator than
> continuing.
>
> -Jason
>
> On Sun, Mar 4, 2018 at 10:14 PM, Guozhang Wang  wrote:
>
> > Hello Richard,
> >
> > Thanks for the proposed KIP. I have a couple of general comments:
> >
> > 1. I'm not sure if piggy-backing the timeout exception on the
> > existing requestTimeoutMs configured in "request.timeout.ms" is a good
> > idea
> > since a) it is a general config that applies for all types of requests,
> and
> > 2) using it to cover all the phases of an API call, including network
> round
> > trip and potential metadata refresh is shown to not be a good idea, as
> > illustrated in KIP-91:
> >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-
> > 91+Provide+Intuitive+User+Timeouts+in+The+Producer
> >
> > In fact, I think in KAFKA-4879 which is aimed for the same issue as
> > KAFKA-6608,
> > Jason has suggested we use a new config for the API. Maybe this would be
> a
> > more intuitive manner than reusing the request.timeout.ms config.
> >
> >
> > 2. Besides the Consumer.position() call, there are a couple of more
> > blocking calls today that could result in infinite blocking:
> > Consumer.commitSync() and Consumer.committed(), should they be considered
> > in this KIP as well?
> >
> > 3. There are a few other APIs that are today relying on
> request.timeout.ms
> > already for breaking the infinite blocking, namely
> Consumer.partitionFor(),
> > Consumer.OffsetAndTimestamp() and Consumer.listTopics(), if we are making
> > the other blocking calls to be relying a new config as suggested in 1)
> > above, should we also change the semantics of these API functions for
> > consistency?
> >
> >
> > Guozhang
> >
> >
> >
> >
> > On Sun, Mar 4, 2018 at 11:13 AM, Richard Yu 
> > wrote:
> >
> > > Hi all,
> > >
> > > I would like to discuss a potential change which would be made to
> > > KafkaConsumer:
> > > https://cwiki.apache.org/confluence/pages/viewpage.
> > action?pageId=75974886
> > >
> > > Thanks,
> > > Richard Yu
> > >
> >
> >
> >
> > --
> > -- Guozhang
> >
>

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Jason Gustafson]

@Guozhang I probably have suggested all options at some point or another,
including most recently, the current KIP! I was thinking that practically
speaking, the request timeout defines how long the user is willing to wait
for a response. The consumer doesn't really have a complex send process
like the producer for any of these APIs, so I wasn't sure how much benefit
there would be from having more granular control over timeouts (in the end,
KIP-91 just adds a single timeout to control the whole send). That said, it
might indeed be better to avoid overloading the config as you suggest since
at least it avoids inconsistency with the producer's usage.

The most flexible option is to add overloads to the consumer so that users
can pass the timeout directly. I'm not sure if that is more or less
annoying than a new config, but I've found config timeouts a little
constraining in practice. For example, I could imagine users wanting to
wait longer for an offset commit operation than a position lookup; if the
latter isn't timely, users can just pause the partition and continue
fetching on others. If you cannot commit offsets, however, it might be
safer for an application to wait availability of the coordinator than
continuing.

-Jason

On Sun, Mar 4, 2018 at 10:14 PM, Guozhang Wang  wrote:

> Hello Richard,
>
> Thanks for the proposed KIP. I have a couple of general comments:
>
> 1. I'm not sure if piggy-backing the timeout exception on the
> existing requestTimeoutMs configured in "request.timeout.ms" is a good
> idea
> since a) it is a general config that applies for all types of requests, and
> 2) using it to cover all the phases of an API call, including network round
> trip and potential metadata refresh is shown to not be a good idea, as
> illustrated in KIP-91:
>
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-
> 91+Provide+Intuitive+User+Timeouts+in+The+Producer
>
> In fact, I think in KAFKA-4879 which is aimed for the same issue as
> KAFKA-6608,
> Jason has suggested we use a new config for the API. Maybe this would be a
> more intuitive manner than reusing the request.timeout.ms config.
>
>
> 2. Besides the Consumer.position() call, there are a couple of more
> blocking calls today that could result in infinite blocking:
> Consumer.commitSync() and Consumer.committed(), should they be considered
> in this KIP as well?
>
> 3. There are a few other APIs that are today relying on request.timeout.ms
> already for breaking the infinite blocking, namely Consumer.partitionFor(),
> Consumer.OffsetAndTimestamp() and Consumer.listTopics(), if we are making
> the other blocking calls to be relying a new config as suggested in 1)
> above, should we also change the semantics of these API functions for
> consistency?
>
>
> Guozhang
>
>
>
>
> On Sun, Mar 4, 2018 at 11:13 AM, Richard Yu 
> wrote:
>
> > Hi all,
> >
> > I would like to discuss a potential change which would be made to
> > KafkaConsumer:
> > https://cwiki.apache.org/confluence/pages/viewpage.
> action?pageId=75974886
> >
> > Thanks,
> > Richard Yu
> >
>
>
>
> --
> -- Guozhang
>

Re: [DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Guozhang Wang]

Hello Richard,

Thanks for the proposed KIP. I have a couple of general comments:

1. I'm not sure if piggy-backing the timeout exception on the
existing requestTimeoutMs configured in "request.timeout.ms" is a good idea
since a) it is a general config that applies for all types of requests, and
2) using it to cover all the phases of an API call, including network round
trip and potential metadata refresh is shown to not be a good idea, as
illustrated in KIP-91:

https://cwiki.apache.org/confluence/display/KAFKA/KIP-91+Provide+Intuitive+User+Timeouts+in+The+Producer

In fact, I think in KAFKA-4879 which is aimed for the same issue as KAFKA-6608,
Jason has suggested we use a new config for the API. Maybe this would be a
more intuitive manner than reusing the request.timeout.ms config.


2. Besides the Consumer.position() call, there are a couple of more
blocking calls today that could result in infinite blocking:
Consumer.commitSync() and Consumer.committed(), should they be considered
in this KIP as well?

3. There are a few other APIs that are today relying on request.timeout.ms
already for breaking the infinite blocking, namely Consumer.partitionFor(),
Consumer.OffsetAndTimestamp() and Consumer.listTopics(), if we are making
the other blocking calls to be relying a new config as suggested in 1)
above, should we also change the semantics of these API functions for
consistency?


Guozhang




On Sun, Mar 4, 2018 at 11:13 AM, Richard Yu 
wrote:

> Hi all,
>
> I would like to discuss a potential change which would be made to
> KafkaConsumer:
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=75974886
>
> Thanks,
> Richard Yu
>



-- 
-- Guozhang

[DISCUSSION] KIP-266: Add TimeoutException to KafkaConsumer#position()

[Richard Yu]

Hi all,

I would like to discuss a potential change which would be made to
KafkaConsumer:
https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=75974886

Thanks,
Richard Yu