### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```If you are writing a general purpose display app, I think, (but I am not at
all certain), that you can ignore this issue. Reasonable polling frequency
on modest velocity timelines will sometimes, but very rarely, miss a tweet.
Also, over time, we're doing things to make this better for everyone. Many
of our projects have the side-effect of reducing K, decreasing the already
low since_id failure odds even further. Some tweet pipeline changes when
live in the last few weeks that dramatically reduce the K distribution for
various user types.

Since I don't know how the Last-Modified time exactly works, I'm going to

Assuming synchronized clocks (or solely the Twitter Clock, if exposed
properly via Last-Modified), given a poll at time t, the newest status is at
least t - n seconds old, and sufficient n, then even a naive since_id
algorithm will be effectively Exactly Once. Assuming that Twitter is running
normally. For a given poll, when the poll time and last update time delta
drops below this n second period, there's a non-zero loss risk.

Just what is n? It is K expressed as time rather than as a discrete count.
For some timelines types, with some classes of users, K is as much as
perhaps 180 seconds. For others, K is less than 1 second. There's some
variability here that we should characterize more carefully internally and
then discuss publicly. I suspect there's a lot to be learned from this
exercise.

Since_id really runs into trouble when any of the following are too great:
the polling frequency, the updating frequency, the roughly-sorted K value.
If you are polling often to reduce display latency, use the Streaming API.
If the timeline moves too fast to capture it all exactly, you should
Streaming API. Does the user really need to see every Bieber at 3 Biebers
Per Second? How would they ever know if they missed 10^-5 of them in a blur?
If you need them all for analysis, consider calculating the confidence
interval given a sample proportion of 1 - 10^6 (6 9s) or so vs. a total
enumeration. Indistinguishable. If you need them for some other purpose, say
CRM, the Streaming API may be the answer.

-John Kalucki

On Fri, Apr 9, 2010 at 2:28 PM, Brian Smith br...@briansmith.org wrote:

John,

I am not polling. I am simply trying to implement a basic “refresh” feature
like every desktop/mobile Twitter app has. Basically, I just want to let
users scroll through their timelines, and be reasonably sure that I am
presenting them with an accurate  complete view of the timeline, while
using as little bandwidth as possible.

When I said “10 seconds old”/“30 seconds old”/etc. I was referring to I was
referring to the age at the time the page of tweets was generated. So,
basically, if the tweet’s timestamp – the response’s Last-Modified time more
than 10,000 ms (from what you said below), you are almost definitely getting
At Least Once behavior if Twitter is operating normally, and you can use
that information to get At Least Once behavior that emulates Exactly Once
behavior with little (usually no) overhead. Is that a correct interpretation
of what you were saying?

Thanks,

Brian

*Sent:* Friday, April 09, 2010 3:31 PM

*Subject:* Re: [twitter-dev] Re: Upcoming changes to the way status IDs
are sequenced

Your second paragraph doesn't quite make sense. The period between your
next poll and the timestamp of the last status is irrelevant. The issue is
solely the magnitude of K on the roughly sorted stream of events that are
applied to the materialized timeline vector. As K varies, so do the odds,
however infinitesimally small, that you will miss a tweet using the last
status id returned. The period between your polls of the API does not affect
this K.

My recommendation is to ignore this issue in nearly every use case. If you
are, however, polling high velocity timelines (including search queries) and
attempting to approximate an Exactly Once QoS, you should, basically, stop
doing that. You are probably wasting resources and you'll probably never get
Exactly Once behavior anyway. Use the Streaming API instead.

-John Kalucki

On Fri, Apr 9, 2010 at 12:20 PM, Brian Smith br...@briansmith.org wrote:

John,

Thank you. That was one of the most informative emails on the Twitter API I
have seen on the list.

Basically, even now, an application should not use an ID of a tweet for
since_id if the tweet is less than 10 seconds old, ignoring service
abnormalities. Probably a larger threshold (30 seconds or even a minute)
would be better, especially when you take```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```Hi John (et al.),

These emails from you are great -- they are exactly the sort of
thoughtful, detailed, specific, technical emails that I would
personally love to see accompany future announcements. I think they
would prevent a fair amount of FUD. Thank you.

I have one stupid question, if you don't mind, though. You refer in
every email to K. What, precisely, does K refer to? What are its
units? (I think I know what it you mean by it, but I'd be interested
to hear precisely.)

Thanks,
Josh

On Sun, Apr 11, 2010 at 2:23 PM, John Kalucki j...@twitter.com wrote:
If you are writing a general purpose display app, I think, (but I am not at
all certain), that you can ignore this issue. Reasonable polling frequency
on modest velocity timelines will sometimes, but very rarely, miss a tweet.
Also, over time, we're doing things to make this better for everyone. Many
of our projects have the side-effect of reducing K, decreasing the already
low since_id failure odds even further. Some tweet pipeline changes when
live in the last few weeks that dramatically reduce the K distribution for
various user types.

Since I don't know how the Last-Modified time exactly works, I'm going to

Assuming synchronized clocks (or solely the Twitter Clock, if exposed
properly via Last-Modified), given a poll at time t, the newest status is at
least t - n seconds old, and sufficient n, then even a naive since_id
algorithm will be effectively Exactly Once. Assuming that Twitter is running
normally. For a given poll, when the poll time and last update time delta
drops below this n second period, there's a non-zero loss risk.

Just what is n? It is K expressed as time rather than as a discrete count.
For some timelines types, with some classes of users, K is as much as
perhaps 180 seconds. For others, K is less than 1 second. There's some
variability here that we should characterize more carefully internally and
then discuss publicly. I suspect there's a lot to be learned from this
exercise.

Since_id really runs into trouble when any of the following are too great:
the polling frequency, the updating frequency, the roughly-sorted K value.
If you are polling often to reduce display latency, use the Streaming API.
If the timeline moves too fast to capture it all exactly, you should
Streaming API. Does the user really need to see every Bieber at 3 Biebers
Per Second? How would they ever know if they missed 10^-5 of them in a blur?
If you need them all for analysis, consider calculating the confidence
interval given a sample proportion of 1 - 10^6 (6 9s) or so vs. a total
enumeration. Indistinguishable. If you need them for some other purpose, say
CRM, the Streaming API may be the answer.

-John Kalucki

On Fri, Apr 9, 2010 at 2:28 PM, Brian Smith br...@briansmith.org wrote:

John,

I am not polling. I am simply trying to implement a basic “refresh”
feature like every desktop/mobile Twitter app has. Basically, I just want to
let users scroll through their timelines, and be reasonably sure that I am
presenting them with an accurate  complete view of the timeline, while
using as little bandwidth as possible.

When I said “10 seconds old”/“30 seconds old”/etc. I was referring to I
was referring to the age at the time the page of tweets was generated. So,
basically, if the tweet’s timestamp – the response’s Last-Modified time more
than 10,000 ms (from what you said below), you are almost definitely getting
At Least Once behavior if Twitter is operating normally, and you can use
that information to get At Least Once behavior that emulates Exactly Once
behavior with little (usually no) overhead. Is that a correct interpretation
of what you were saying?

Thanks,

Brian

Sent: Friday, April 09, 2010 3:31 PM
Subject: Re: [twitter-dev] Re: Upcoming changes to the way status IDs are
sequenced

Your second paragraph doesn't quite make sense. The period between your
next poll and the timestamp of the last status is irrelevant. The issue is
solely the magnitude of K on the roughly sorted stream of events that are
applied to the materialized timeline vector. As K varies, so do the odds,
however infinitesimally small, that you will miss a tweet using the last
status id returned. The period between your polls of the API does not affect
this K.

My recommendation is to ignore this issue in nearly every use case. If you
are, however, polling high velocity timelines (including search queries) and
attempting to approximate an Exactly Once QoS, you should, basically, stop
doing that. You are probably wasting resources and you'll probably never get```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```.

When I said “10 seconds old”/“30 seconds old”/etc. I was referring to I
was referring to the age at the time the page of tweets was generated.
So,
basically, if the tweet’s timestamp – the response’s Last-Modified time
more
than 10,000 ms (from what you said below), you are almost definitely
getting
At Least Once behavior if Twitter is operating normally, and you can use
that information to get At Least Once behavior that emulates Exactly
Once
behavior with little (usually no) overhead. Is that a correct
interpretation
of what you were saying?

Thanks,

Brian

Kalucki
Sent: Friday, April 09, 2010 3:31 PM
Subject: Re: [twitter-dev] Re: Upcoming changes to the way status IDs
are
sequenced

Your second paragraph doesn't quite make sense. The period between your
next poll and the timestamp of the last status is irrelevant. The issue
is
solely the magnitude of K on the roughly sorted stream of events that
are
applied to the materialized timeline vector. As K varies, so do the
odds,
however infinitesimally small, that you will miss a tweet using the last
status id returned. The period between your polls of the API does not
affect
this K.

My recommendation is to ignore this issue in nearly every use case. If
you
are, however, polling high velocity timelines (including search queries)
and
attempting to approximate an Exactly Once QoS, you should, basically,
stop
doing that. You are probably wasting resources and you'll probably never
get
Exactly Once behavior anyway. Use the Streaming API instead.

-John Kalucki

On Fri, Apr 9, 2010 at 12:20 PM, Brian Smith br...@briansmith.org
wrote:

John,

Thank you. That was one of the most informative emails on the Twitter
API
I have seen on the list.

Basically, even now, an application should not use an ID of a tweet for
since_id if the tweet is less than 10 seconds old, ignoring service
abnormalities. Probably a larger threshold (30 seconds or even a minute)
would be better, especially when you take into consideration the
likelihood
of clock skew between the servers that generate the timestamps.

I think this is information that would be useful to have added to the
API
documentation, as I know many applications are taking a much more naive
approach to pagination.

Thanks again,

Brian

Kalucki
Sent: Friday, April 09, 2010 1:20 PM

Subject: Re: [twitter-dev] Re: Upcoming changes to the way status IDs
are
sequenced

architecture, especially around how we materialize and present timeline
vectors and just what QoS we're really offering. This new scheme does
not
significantly, or perhaps even observably, make the existing issues
around
since_id any better or any worse. And I'm being very precise here. The
since_id situation is such that the few milliseconds skew possible in
Snowflake are practically irrelevant and lost in the noise of a 4 to 6
orders-of-magnitude misconception. (That's a very big misconception.)

If you do not know the rough ordering of our event stream as it applied
to
the materialized timeline vectors and also the expected rate of change
on
the timeline in question, you cannot make good choices about making
since_id
perfect. But, neither you should you try to make it perfect, nor should
you

Mark's
advice: In the existing continuously increasing id generation scheme on
the
sufficient overlap in nearly all cases, but even this could be lossy in
the
face of severe operational issues -- issues of a type that we haven't
seen
in many many months. The search API has a different K in its rough
ordering,
so you might need more like 10,000 ids. In the new Snowflake scheme, I'd
for
search APIs.

Despite all this, things still could go wrong. An engineer here is known
for pointing out that even things that almost never ever happen, happen
all
the time on the Twitter system. Now, just because they are happening, to
someone, all the time, doesn't mean that they'll ever ever happen to you
or
your users in a thousand years -- but some's getting hit with it,
somewhere,
a few times a day.

The above schemes no longer treat the id as an opaque unique ordered
identifier. And woe lies in wait for you```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```On Sun, Apr 11, 2010 at 5:14 PM, John Kalucki j...@twitter.com wrote:

This is useful stuff for dealing with infinite sequences of events -- like,
picking a random example, the insertion of new tweets into a materialized
timeline (a cache of the timeline vector).

The Twitter stream is an infinite sequence of events... now that's serious

Sorry, just had to say it.

Of course, some infinities are bigger than others.

Nick

--
To unsubscribe, reply using remove me as the subject.

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```On Thu, Apr 08, 2010 at 05:03:29PM -0700, Naveen wrote:
However, I wanted to be clear and feel it should be made obvious that
with this change, there is a possibility that a tweet may not be
delivered to client if the implementation of how since_id is currently
used is not updated to cover the case.  I still envision the situation
as more likely than you seem to believe and figure as tweet velocity
increases, the likelihood will also increase; But I am assuming have
better data to support your viewpoint than I and shall defer.

Maybe I'm just missing something here, but it seems trivial to fix on
Twitter's side (enough so that I assume it's what they've been planning
from the start to do):  Only return tweets from closed buckets.

We are guaranteed that the buckets will be properly ordered.  The order
will only be randomized within a bucket.  Therefore, by only returning
tweets from buckets which are no longer receiving new tweets, since_id
works and will never miss a tweet.

And, yes, this does mean a slight delay in getting the tweets out
because they have to wait a few milliseconds for their bucket to close
before being exposed to calls which can use since_id, plus maybe a
little longer for the contents of that bucket to be distributed to
multiple servers.  That's still going to only take time comparable to
round-trip times for an HTTP request to fetch the data for display to a
user and be far, far less than the average refresh delay required by
those clients which fall under the API rate limit.  I submit, therefore,
that any such delay caused by waiting for buckets to close will be
inconsequential.

--
Dave Sherohman

```

### RE: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```John,

Thank you. That was one of the most informative emails on the Twitter API I
have seen on the list.

Basically, even now, an application should not use an ID of a tweet for
since_id if the tweet is less than 10 seconds old, ignoring service
abnormalities. Probably a larger threshold (30 seconds or even a minute)
would be better, especially when you take into consideration the likelihood
of clock skew between the servers that generate the timestamps.

I think this is information that would be useful to have added to the API
documentation, as I know many applications are taking a much more naive
approach to pagination.

Thanks again,

Brian

Sent: Friday, April 09, 2010 1:20 PM
Subject: Re: [twitter-dev] Re: Upcoming changes to the way status IDs are
sequenced

architecture, especially around how we materialize and present timeline
vectors and just what QoS we're really offering. This new scheme does not
significantly, or perhaps even observably, make the existing issues around
since_id any better or any worse. And I'm being very precise here. The
since_id situation is such that the few milliseconds skew possible in
Snowflake are practically irrelevant and lost in the noise of a 4 to 6
orders-of-magnitude misconception. (That's a very big misconception.)

If you do not know the rough ordering of our event stream as it applied to
the materialized timeline vectors and also the expected rate of change on
the timeline in question, you cannot make good choices about making since_id
perfect. But, neither you should you try to make it perfect, nor should you

advice: In the existing continuously increasing id generation scheme on the
sufficient overlap in nearly all cases, but even this could be lossy in the
face of severe operational issues -- issues of a type that we haven't seen
in many many months. The search API has a different K in its rough ordering,
so you might need more like 10,000 ids. In the new Snowflake scheme, I'd
overlap by about 5000 milliseconds for twitter.com APIs and 10,000 ms for
search APIs.

Despite all this, things still could go wrong. An engineer here is known for
pointing out that even things that almost never ever happen, happen all the
time on the Twitter system. Now, just because they are happening, to
someone, all the time, doesn't mean that they'll ever ever happen to you or
your users in a thousand years -- but some's getting hit with it, somewhere,
a few times a day.

The above schemes no longer treat the id as an opaque unique ordered
identifier. And woe lies in wait for you as changes are made to these ids.
Woe. You also need to deduplicate. Be very careful and understand fully what
you summon by breaking this semantic contract.

In the end, since_id issues go away on the Streaming API, and other than
around various start-up discontinuities, you can ignore this issue. I'll be
talking about Rough Ordering, among other things Streaming, at the Chirp
conference. Come geek out.

-John Kalucki

On Fri, Apr 9, 2010 at 1:58 AM, Dave Sherohman d...@fishtwits.com wrote:

On Thu, Apr 08, 2010 at 05:03:29PM -0700, Naveen wrote:
However, I wanted to be clear and feel it should be made obvious that
with this change, there is a possibility that a tweet may not be
delivered to client if the implementation of how since_id is currently
used is not updated to cover the case.  I still envision the situation
as more likely than you seem to believe and figure as tweet velocity
increases, the likelihood will also increase; But I am assuming have
better data to support your viewpoint than I and shall defer.

Maybe I'm just missing something here, but it seems trivial to fix on
Twitter's side (enough so that I assume it's what they've been planning
from the start to do):  Only return tweets from closed buckets.

We are guaranteed that the buckets will be properly ordered.  The order
will only be randomized within a bucket.  Therefore, by only returning
tweets from buckets which are no longer receiving new tweets, since_id
works and will never miss a tweet.

And, yes, this does mean a slight delay in getting the tweets out
because they have to wait a few milliseconds for their bucket to close
before being exposed to calls which can use since_id, plus maybe a
little longer for the contents of that bucket to be distributed to
multiple servers.  That's still going to only take time comparable to
round-trip times for an HTTP request to fetch the data for display to a
user and be far, far less than the average refresh delay required by
those clients which fall under```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```Your second paragraph doesn't quite make sense. The period between your next
poll and the timestamp of the last status is irrelevant. The issue is solely
the magnitude of K on the roughly sorted stream of events that are applied
to the materialized timeline vector. As K varies, so do the odds, however
infinitesimally small, that you will miss a tweet using the last status id
returned. The period between your polls of the API does not affect this K.

My recommendation is to ignore this issue in nearly every use case. If you
are, however, polling high velocity timelines (including search queries) and
attempting to approximate an Exactly Once QoS, you should, basically, stop
doing that. You are probably wasting resources and you'll probably never get
Exactly Once behavior anyway. Use the Streaming API instead.

-John Kalucki

On Fri, Apr 9, 2010 at 12:20 PM, Brian Smith br...@briansmith.org wrote:

John,

Thank you. That was one of the most informative emails on the Twitter API I
have seen on the list.

Basically, even now, an application should not use an ID of a tweet for
since_id if the tweet is less than 10 seconds old, ignoring service
abnormalities. Probably a larger threshold (30 seconds or even a minute)
would be better, especially when you take into consideration the likelihood
of clock skew between the servers that generate the timestamps.

I think this is information that would be useful to have added to the API
documentation, as I know many applications are taking a much more naive
approach to pagination.

Thanks again,

Brian

Kalucki
*Sent:* Friday, April 09, 2010 1:20 PM

*Subject:* Re: [twitter-dev] Re: Upcoming changes to the way status IDs
are sequenced

architecture, especially around how we materialize and present timeline
vectors and just what QoS we're really offering. This new scheme does not
significantly, or perhaps even observably, make the existing issues around
since_id any better or any worse. And I'm being very precise here. The
since_id situation is such that the few milliseconds skew possible in
Snowflake are practically irrelevant and lost in the noise of a 4 to 6
orders-of-magnitude misconception. (That's a very big misconception.)

If you do not know the rough ordering of our event stream as it applied to
the materialized timeline vectors and also the expected rate of change on
the timeline in question, you cannot make good choices about making since_id
perfect. But, neither you should you try to make it perfect, nor should you

advice: In the existing continuously increasing id generation scheme on the
sufficient overlap in nearly all cases, but even this could be lossy in the
face of severe operational issues -- issues of a type that we haven't seen
in many many months. The search API has a different K in its rough ordering,
so you might need more like 10,000 ids. In the new Snowflake scheme, I'd
overlap by about 5000 milliseconds for twitter.com APIs and 10,000 ms for
search APIs.

Despite all this, things still could go wrong. An engineer here is known
for pointing out that even things that almost never ever happen, happen all
the time on the Twitter system. Now, just because they are happening, to
someone, all the time, doesn't mean that they'll ever ever happen to you or
your users in a thousand years -- but some's getting hit with it, somewhere,
a few times a day.

The above schemes no longer treat the id as an opaque unique ordered
identifier. And woe lies in wait for you as changes are made to these ids.
Woe. You also need to deduplicate. Be very careful and understand fully what
you summon by breaking this semantic contract.

In the end, since_id issues go away on the Streaming API, and other than
around various start-up discontinuities, you can ignore this issue. I'll be
talking about Rough Ordering, among other things Streaming, at the Chirp
conference. Come geek out.

-John Kalucki

On Fri, Apr 9, 2010 at 1:58 AM, Dave Sherohman d...@fishtwits.com wrote:

On Thu, Apr 08, 2010 at 05:03:29PM -0700, Naveen wrote:
However, I wanted to be clear and feel it should be made obvious that
with this change, there is a possibility that a tweet may not be
delivered to client if the implementation of how since_id is currently
used is not updated to cover the case.  I still envision the situation
as more likely than you seem to believe and figure as tweet velocity
increases, the likelihood will also increase; But I am assuming have```

### RE: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```John,

I am not polling. I am simply trying to implement a basic refresh feature
like every desktop/mobile Twitter app has. Basically, I just want to let
users scroll through their timelines, and be reasonably sure that I am
presenting them with an accurate  complete view of the timeline, while
using as little bandwidth as possible.

When I said 10 seconds old/30 seconds old/etc. I was referring to I was
referring to the age at the time the page of tweets was generated. So,
basically, if the tweet's timestamp - the response's Last-Modified time more
than 10,000 ms (from what you said below), you are almost definitely getting
At Least Once behavior if Twitter is operating normally, and you can use
that information to get At Least Once behavior that emulates Exactly Once
behavior with little (usually no) overhead. Is that a correct interpretation
of what you were saying?

Thanks,

Brian

Sent: Friday, April 09, 2010 3:31 PM
Subject: Re: [twitter-dev] Re: Upcoming changes to the way status IDs are
sequenced

Your second paragraph doesn't quite make sense. The period between your next
poll and the timestamp of the last status is irrelevant. The issue is solely
the magnitude of K on the roughly sorted stream of events that are applied
to the materialized timeline vector. As K varies, so do the odds, however
infinitesimally small, that you will miss a tweet using the last status id
returned. The period between your polls of the API does not affect this K.

My recommendation is to ignore this issue in nearly every use case. If you
are, however, polling high velocity timelines (including search queries) and
attempting to approximate an Exactly Once QoS, you should, basically, stop
doing that. You are probably wasting resources and you'll probably never get
Exactly Once behavior anyway. Use the Streaming API instead.

-John Kalucki

On Fri, Apr 9, 2010 at 12:20 PM, Brian Smith br...@briansmith.org wrote:

John,

Thank you. That was one of the most informative emails on the Twitter API I
have seen on the list.

Basically, even now, an application should not use an ID of a tweet for
since_id if the tweet is less than 10 seconds old, ignoring service
abnormalities. Probably a larger threshold (30 seconds or even a minute)
would be better, especially when you take into consideration the likelihood
of clock skew between the servers that generate the timestamps.

I think this is information that would be useful to have added to the API
documentation, as I know many applications are taking a much more naive
approach to pagination.

Thanks again,

Brian

Sent: Friday, April 09, 2010 1:20 PM

Subject: Re: [twitter-dev] Re: Upcoming changes to the way status IDs are
sequenced

architecture, especially around how we materialize and present timeline
vectors and just what QoS we're really offering. This new scheme does not
significantly, or perhaps even observably, make the existing issues around
since_id any better or any worse. And I'm being very precise here. The
since_id situation is such that the few milliseconds skew possible in
Snowflake are practically irrelevant and lost in the noise of a 4 to 6
orders-of-magnitude misconception. (That's a very big misconception.)

If you do not know the rough ordering of our event stream as it applied to
the materialized timeline vectors and also the expected rate of change on
the timeline in question, you cannot make good choices about making since_id
perfect. But, neither you should you try to make it perfect, nor should you

advice: In the existing continuously increasing id generation scheme on the
sufficient overlap in nearly all cases, but even this could be lossy in the
face of severe operational issues -- issues of a type that we haven't seen
in many many months. The search API has a different K in its rough ordering,
so you might need more like 10,000 ids. In the new Snowflake scheme, I'd
overlap by about 5000 milliseconds for twitter.com APIs and 10,000 ms for
search APIs.

Despite all this, things still could go wrong. An engineer here is known for
pointing out that even things that almost never ever happen, happen all the
time on the Twitter system. Now, just because they are happening, to
someone, all the time, doesn't mean that they'll ever ever happen to you or
your users in a thousand years -- but some's getting hit with it, somewhere,
a few times a day```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```Thank you for the feedback.  It's great to hear about the variety of use
cases people have for the API, and in particular all the different ways
people are using IDs. To alleviate some of the concerns raised in this
thread we thought it would be useful to give more details about how we plan
to generate IDs

1) IDs are still 64-bit integers.  This should minimize any migration pains.
2) You can still sort on ID.  Within a few millieconds you may get out of
order results, but for most use cases this shouldn't be an issue.
3) since_id will still work (within the caveats given above).
4) We will provide a way to backfill from the streaming API.
5) You cannot use the generated ID to reverse engineer tweet velocity.  Note
that you can still use the streaming API to determine the rate of public
statuses.

1) At some point we will likely start using this as an ID for direct
messages too
2) We will almost certainly open source the ID generation code, probably
before we actually cut over to using it.
3) We STRONGLY suggest that you treat IDs as roughly sorted (roughly being
within a few ms buckets), opaque 64-bit integers.  We may need to change the
scheme again at some point in the future, and want to minimize migration
pains should we need to do this.

Hopefully this puts you more at ease with the changes we're making.  If it
raises new concerns, please let us know!

---Mark

On Mon, Apr 5, 2010 at 4:18 PM, M. Edward (Ed) Borasky zn...@comcast.netwrote:

On 04/05/2010 12:55 AM, Tim Haines wrote:

On Fri, Apr 2, 2010 at 6:47 AM, Dewald Pretorius dpr...@gmail.com
wrote:

Mark,

It's extremely important where you have two bots that reply to each
others' tweets. With incorrectly sorted tweets, you get conversations
that look completely unnatural.

On Apr 1, 1:39 pm, Mark McBride mmcbr...@twitter.com wrote:
Just out of curiosity, what applications are you building that require
sub-second sorting resolution for tweets?

Yeah - my bot laughed too ;-)
--

A mathematician is a device for turning coffee into theorems. ~ Paul
Erdős

--
To unsubscribe, reply using remove me as the subject.

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```On Thu, Apr 1, 2010 at 10:47 AM, Dewald Pretorius dpr...@gmail.com wrote:

Mark,

It's extremely important where you have two bots that reply to each
others' tweets. With incorrectly sorted tweets, you get conversations
that look completely unnatural.

I'd love to see an example of two bots replying to each other and looking
entirely natural!

We all knew this sort of thing was going on, removing the pesky humans from
the loop, but I always thought it was unintentional.

There's a science fiction story in there somewhere.

Nick

--
Subscription settings:

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```On Thu, Apr 8, 2010 at 5:39 PM, Nick Arnett nick.arn...@gmail.com wrote:

I'd love to see an example of two bots replying to each other and looking
entirely natural!

We all knew this sort of thing was going on, removing the pesky humans from
the loop, but I always thought it was unintentional.

There's a science fiction story in there somewhere.

Do Twitterbots dream of electric sheep?

--
Subscription settings:

```

### RE: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```What does “within the caveats given above” mean? Either since_id will work or
it won’t. It seems to me that if IDs are only in a “rough” order, since_id
won’t work—in particular, there is a possibility that paging through tweets
using since_id will completely skip over some tweets.

My concern is that, since tweets will not be serialized at the time they are
written, there will be a race condition between me making a request and users
posting new statuses. That is, I could get a response with the largest id in
the response being X that gets evaluated just before a tweet (X-1) has been
saved in the database; If so, when I issue a request with since_id=X, my
program will never see the newer tweet (X-1).

Are you going to change the implementation of the timeline methods so that they
never return a tweet with ID X until all nodes in the cluster guarantee that
they won’t create a new tweet with an ID less than X?

I implement the following logic:

1.  Let LATEST start out as the earliest tweet available in the user’s
timeline.

2.  Make a request with since_id={LATEST}, which returns a set of tweets T.

3.  If T is empty then stop.

4.  Let LATEST= max({ id(t), for all t in T}).

5.  Goto 2.

Will I be guaranteed not to skip over any tweets in the timeline using this
logic? If not, what do I need to do to ensure I get them all?

Thanks,

Brian

Sent: Thursday, April 08, 2010 5:10 PM
Subject: Re: [twitter-dev] Re: Upcoming changes to the way status IDs are
sequenced

Thank you for the feedback.  It's great to hear about the variety of use cases
people have for the API, and in particular all the different ways people are
using IDs. To alleviate some of the concerns raised in this thread we thought
it would be useful to give more details about how we plan to generate IDs

1) IDs are still 64-bit integers.  This should minimize any migration pains.

2) You can still sort on ID.  Within a few millieconds you may get out of order
results, but for most use cases this shouldn't be an issue.

3) since_id will still work (within the caveats given above).

4) We will provide a way to backfill from the streaming API.

5) You cannot use the generated ID to reverse engineer tweet velocity.  Note
that you can still use the streaming API to determine the rate of public
statuses.

1) At some point we will likely start using this as an ID for direct messages
too

2) We will almost certainly open source the ID generation code, probably before
we actually cut over to using it.

3) We STRONGLY suggest that you treat IDs as roughly sorted (roughly being
within a few ms buckets), opaque 64-bit integers.  We may need to change the
scheme again at some point in the future, and want to minimize migration pains
should we need to do this.

Hopefully this puts you more at ease with the changes we're making.  If it
raises new concerns, please let us know!

---Mark

On Mon, Apr 5, 2010 at 4:18 PM, M. Edward (Ed) Borasky zn...@comcast.net
wrote:

On 04/05/2010 12:55 AM, Tim Haines wrote:

On Fri, Apr 2, 2010 at 6:47 AM, Dewald Pretorius dpr...@gmail.com wrote:

Mark,

It's extremely important where you have two bots that reply to each
others' tweets. With incorrectly sorted tweets, you get conversations
that look completely unnatural.

On Apr 1, 1:39 pm, Mark McBride mmcbr...@twitter.com wrote:
Just out of curiosity, what applications are you building that require
sub-second sorting resolution for tweets?

Yeah - my bot laughed too ;-)

--

A mathematician is a device for turning coffee into theorems. ~ Paul Erdős

--

To unsubscribe, reply using remove me as the subject.

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```It's a possibility, but by no means a probability.  Note that you can
mitigate this by using the newest tweet that is outside your danger zone.
For example in a sequence of tweets t1, t2 ... ti ... tn with creation
times c1, c2 ... ci ... cn and a comfort threshold e you could use since_id
from the latest ti such that c1 - ci  e.

---Mark

On Thu, Apr 8, 2010 at 4:27 PM, Naveen knig...@gmail.com wrote:

This was my initial concern with the randomly generated ids that I
brought up, though I think Brian described it better than I.

It simply seems very likely that when using since_id to populate newer
tweets for the user, that some tweets will never be seen, because the
since_id of the last message received will be larger than one
generated 1ms later.

With the random generation of ids, I can see two way guarantee
delivery of all tweets in a users timeline
1. Page forwards and backwards to ensure no tweets generated at or
near the same time as the newest one did not receive a lower id. This
will be very expensive for a mobile client not to mention complicate
any refresh algorithms significantly.
2. Given that we know how IDs are generated (i.e. which bits represent
the time) we can simply over request by decrementing the since_id time
bits, by a second or two and filter out duplicates. (again, not really
ideal for mobile clients where battery life is an issue, plus it then
makes the implementation very dependent on twitters id format
remaining stable)

Please anyone explain if Brian and I are misinterpreting this as a
very real possibility of never displaying some tweets in a time line,
without changing how we request data from twitter (i.e. since_id
doesn't break)

--Naveen Ayyagari
@knight9
@SocialScope

On Apr 8, 7:01 pm, Brian Smith br...@briansmith.org wrote:
What does “within the caveats given above” mean? Either since_id will
work or it won’t. It seems to me that if IDs are only in a “rough” order,
since_id won’t work—in particular, there is a possibility that paging
through tweets using since_id will completely skip over some tweets.

My concern is that, since tweets will not be serialized at the time they
are written, there will be a race condition between me making a request and
users posting new statuses. That is, I could get a response with the largest
id in the response being X that gets evaluated just before a tweet (X-1) has
been saved in the database; If so, when I issue a request with since_id=X,
my program will never see the newer tweet (X-1).

Are you going to change the implementation of the timeline methods so
that they never return a tweet with ID X until all nodes in the cluster
guarantee that they won’t create a new tweet with an ID less than X?

I implement the following logic:

1.  Let LATEST start out as the earliest tweet available in the
user’s timeline.

2.  Make a request with since_id={LATEST}, which returns a set of
tweets T.

3.  If T is empty then stop.

4.  Let LATEST= max({ id(t), for all t in T}).

5.  Goto 2.

Will I be guaranteed not to skip over any tweets in the timeline using
this logic? If not, what do I need to do to ensure I get them all?

Thanks,

Brian

Sent: Thursday, April 08, 2010 5:10 PM
Subject: Re: [twitter-dev] Re: Upcoming changes to the way status IDs are
sequenced

Thank you for the feedback.  It's great to hear about the variety of use
cases people have for the API, and in particular all the different ways
people are using IDs. To alleviate some of the concerns raised in this
thread we thought it would be useful to give more details about how we plan
to generate IDs

1) IDs are still 64-bit integers.  This should minimize any migration
pains.

2) You can still sort on ID.  Within a few millieconds you may get out of
order results, but for most use cases this shouldn't be an issue.

3) since_id will still work (within the caveats given above).

4) We will provide a way to backfill from the streaming API.

5) You cannot use the generated ID to reverse engineer tweet velocity.
Note that you can still use the streaming API to determine the rate of
public statuses.

1) At some point we will likely start using this as an ID for direct
messages too

2) We will almost certainly open source the ID generation code, probably
before we actually cut over to using it.

3) We STRONGLY suggest that you treat IDs as roughly sorted (roughly
being within a few ms buckets), opaque 64-bit integers.  We may need to
change the scheme again at some point in the future, and want to minimize
migration pains should we need to do this.

Hopefully this puts you more at ease with the changes we're```

### RE: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```Mark, thank you for taking the time to respond.

What is the smallest “comfort threshold” that will guarantee that we will see
all the tweets, with none skipped over and the fewest tweets returned multiple
times?

Let’s say the comfort threshold was 2 seconds. It seems to me like there could
realistically be dozens or hundreds of tweets within those two seconds in a
single timeline, and a request that used the logic you mentioned would return
an entire page (200 tweets) consisting of tweets that the application already
nothing useful for it, and not be able to make any progress because its
since_id would get “stuck”. This is at odds with many (most?) applications goal
in using since_id, which is to transfer as little data as possible.

It seems like a better alternative would a new parameter that says “don’t give
me any tweets that are less than X seconds old,” where X seconds is the
comfort threshold. That way, the application may lag behind by a few of
seconds, but at least it would be able to confidently page through the timeline
without excessive data transfer. Without such a mechanism, it looks like this
change will be a significant degradation of service that result in
applications’ “refresh” features becoming either unreliable or very wasteful.

But, is it realistic for applications to expect the Twitter cluster to be in
sync within 2 seconds? 10 seconds? 30 seconds? That is the part that is unclear
to me.

Thanks again,

Brian

Sent: Thursday, April 08, 2010 6:38 PM
Subject: Re: [twitter-dev] Re: Upcoming changes to the way status IDs are
sequenced

It's a possibility, but by no means a probability.  Note that you can mitigate
this by using the newest tweet that is outside your danger zone.  For example
in a sequence of tweets t1, t2 ... ti ... tn with creation times c1, c2 ... ci
... cn and a comfort threshold e you could use since_id from the latest ti such
that c1 - ci  e.

---Mark

On Thu, Apr 8, 2010 at 4:27 PM, Naveen knig...@gmail.com wrote:

This was my initial concern with the randomly generated ids that I
brought up, though I think Brian described it better than I.

It simply seems very likely that when using since_id to populate newer
tweets for the user, that some tweets will never be seen, because the
since_id of the last message received will be larger than one
generated 1ms later.

With the random generation of ids, I can see two way guarantee
delivery of all tweets in a users timeline
1. Page forwards and backwards to ensure no tweets generated at or
near the same time as the newest one did not receive a lower id. This
will be very expensive for a mobile client not to mention complicate
any refresh algorithms significantly.
2. Given that we know how IDs are generated (i.e. which bits represent
the time) we can simply over request by decrementing the since_id time
bits, by a second or two and filter out duplicates. (again, not really
ideal for mobile clients where battery life is an issue, plus it then
makes the implementation very dependent on twitters id format
remaining stable)

Please anyone explain if Brian and I are misinterpreting this as a
very real possibility of never displaying some tweets in a time line,
without changing how we request data from twitter (i.e. since_id
doesn't break)

--Naveen Ayyagari
@knight9
@SocialScope

On Apr 8, 7:01 pm, Brian Smith br...@briansmith.org wrote:
What does “within the caveats given above” mean? Either since_id will work or
it won’t. It seems to me that if IDs are only in a “rough” order, since_id
won’t work—in particular, there is a possibility that paging through tweets
using since_id will completely skip over some tweets.

My concern is that, since tweets will not be serialized at the time they are
written, there will be a race condition between me making a request and users
posting new statuses. That is, I could get a response with the largest id in
the response being X that gets evaluated just before a tweet (X-1) has been
saved in the database; If so, when I issue a request with since_id=X, my
program will never see the newer tweet (X-1).

Are you going to change the implementation of the timeline methods so that
they never return a tweet with ID X until all nodes in the cluster guarantee
that they won’t create a new tweet with an ID less than X?

I implement the following logic:

1.  Let LATEST start out as the earliest tweet available in the user’s
timeline.

2.  Make a request with since_id={LATEST}, which returns a set of tweets
T.

3.  If T is empty then stop.

4.  Let LATEST= max({ id(t), for all t in T}).

5.  Goto 2.

Will I be guaranteed```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```This made me laugh.  Hard.

On Fri, Apr 2, 2010 at 6:47 AM, Dewald Pretorius dpr...@gmail.com wrote:

Mark,

It's extremely important where you have two bots that reply to each
others' tweets. With incorrectly sorted tweets, you get conversations
that look completely unnatural.

On Apr 1, 1:39 pm, Mark McBride mmcbr...@twitter.com wrote:
Just out of curiosity, what applications are you building that require
sub-second sorting resolution for tweets?

---Mark

On Wed, Mar 31, 2010 at 11:01 PM, Aki yoru.fuku...@gmail.com wrote:
It actually makes sense to use tweet ID to sort tweets, because
timestamp is not a valid source of information for accurate sorting.
It is a very common case to have multiple tweets posted at the exact
same second, and it is not possible to reproduce the correct ordering
of tweets on the client side. This can be improved by having better
precision for timestamp (maybe milliseconds), but it is still possible
to get tweets posted at the exact same milliseconds (although it is
very rare).

If Twitter really needs to change the tweet ID scheme, I think better
solution for sorting is required to be provided through API.

On Mar 27, 7:41 am, Taylor Singletary taylorsinglet...@twitter.com
wrote:
Hi Developers,

It's no secret that Twitter is growing exponentially. The tweets keep
coming
with ever increasing velocity, thanks in large part to your great
applications.

Twitter has adapted to the increasing number of tweets in ways that
have
affected you in the past: We moved from 32 bit unsigned integers to
64-bit
unsigned integers for status IDs some time ago. You all weathered
that
storm
with ease. The tweetapoclypse was averted, and the tweets kept
flowing.

Now we're reaching the scalability limit of our current tweet ID
generation
scheme. Unlike the previous tweet ID migrations, the solution to the
current
issue is significantly different. However, in most cases the new
approach
we
will take will not result in any noticeable differences to you the
developer

We are planning to replace our current sequential tweet ID generation
routine with a simple, more scalable solution. IDs will still be
64-bit
unsigned integers. However, this new solution is no longer guaranteed
to
generate sequential IDs.  Instead IDs will be derived based on time:
the
most significant bits being sourced from a timestamp and the least
significant bits will be effectively random.

Please don't depend on the exact format of the ID. As our
infrastructure
needs evolve, we might need to tweak the generation algorithm again.

If you've been trying to divine meaning from status IDs aside from
their
role as a primary key, you won't be able to anymore. Likewise for
usage
of
IDs in mathematical operations -- for instance, subtracting two
status
IDs
to determine the number of tweets in between will no longer be
possible.

For the majority of applications we think this scheme switch will be
a
non-event. Before implementing these changes, we'd like to know if
your
applications currently depend on the sequential nature of IDs. Do you
depend
on the density of the tweet sequence being constant?  Are you trying
to
analyze the IDs as anything other than opaque, ordered identifiers?
Aside
for guaranteed sequential tweet ID ordering, what APIs can we provide
you
to

Taylor Singletary

--
To unsubscribe, reply using remove me as the subject.- Hide quoted
text -

- Show quoted text -

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```On 04/05/2010 12:55 AM, Tim Haines wrote:

On Fri, Apr 2, 2010 at 6:47 AM, Dewald Pretorius dpr...@gmail.com wrote:

Mark,

It's extremely important where you have two bots that reply to each
others' tweets. With incorrectly sorted tweets, you get conversations
that look completely unnatural.

On Apr 1, 1:39 pm, Mark McBride mmcbr...@twitter.com wrote:
Just out of curiosity, what applications are you building that require
sub-second sorting resolution for tweets?

Yeah - my bot laughed too ;-)
--

A mathematician is a device for turning coffee into theorems. ~ Paul Erdős

--
To unsubscribe, reply using remove me as the subject.

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```Just out of curiosity, what applications are you building that require
sub-second sorting resolution for tweets?

---Mark

On Wed, Mar 31, 2010 at 11:01 PM, Aki yoru.fuku...@gmail.com wrote:

It actually makes sense to use tweet ID to sort tweets, because
timestamp is not a valid source of information for accurate sorting.
It is a very common case to have multiple tweets posted at the exact
same second, and it is not possible to reproduce the correct ordering
of tweets on the client side. This can be improved by having better
precision for timestamp (maybe milliseconds), but it is still possible
to get tweets posted at the exact same milliseconds (although it is
very rare).

If Twitter really needs to change the tweet ID scheme, I think better
solution for sorting is required to be provided through API.

On Mar 27, 7:41 am, Taylor Singletary taylorsinglet...@twitter.com
wrote:
Hi Developers,

It's no secret that Twitter is growing exponentially. The tweets keep
coming
with ever increasing velocity, thanks in large part to your great
applications.

Twitter has adapted to the increasing number of tweets in ways that have
affected you in the past: We moved from 32 bit unsigned integers to
64-bit
unsigned integers for status IDs some time ago. You all weathered that
storm
with ease. The tweetapoclypse was averted, and the tweets kept flowing.

Now we're reaching the scalability limit of our current tweet ID
generation
scheme. Unlike the previous tweet ID migrations, the solution to the
current
issue is significantly different. However, in most cases the new approach
we
will take will not result in any noticeable differences to you the
developer

We are planning to replace our current sequential tweet ID generation
routine with a simple, more scalable solution. IDs will still be 64-bit
unsigned integers. However, this new solution is no longer guaranteed to
generate sequential IDs.  Instead IDs will be derived based on time: the
most significant bits being sourced from a timestamp and the least
significant bits will be effectively random.

Please don't depend on the exact format of the ID. As our infrastructure
needs evolve, we might need to tweak the generation algorithm again.

If you've been trying to divine meaning from status IDs aside from their
role as a primary key, you won't be able to anymore. Likewise for usage
of
IDs in mathematical operations -- for instance, subtracting two status
IDs
to determine the number of tweets in between will no longer be possible.

For the majority of applications we think this scheme switch will be a
non-event. Before implementing these changes, we'd like to know if your
applications currently depend on the sequential nature of IDs. Do you
depend
on the density of the tweet sequence being constant?  Are you trying to
analyze the IDs as anything other than opaque, ordered identifiers? Aside
for guaranteed sequential tweet ID ordering, what APIs can we provide you
to

Taylor Singletary

--
To unsubscribe, reply using remove me as the subject.

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```On Wed, Mar 31, 2010 at 07:30:00AM -0700, eugene.man...@gmail.com wrote:
Second that. Our app continuously retrieves feeds of individual users
and lists. Monotonically increasing are required to be able to do that
(using since_id).
[...]

Since the most significant bits are generated from a timestamp, later
tweets will always have a higher number than earlier ones (except in
the case of the black hole explorer probe tweeting its progress from
within the event horizon).

To illustrate this with decimal numbers from 0-9:

If two users post three tweets each in the space of three seconds,
they may space like this (the first digit is the timestamp, the second
is the random digit):

User 1: 05
User 2: 06
User 1: 17
User 2: 12
User 1: 27
User 2: 29

Tweets 12 and 17 are out of order, but they're not really in
order, since they happened at the same time (depending on the
precision of the timestamp) by different users. User 1's tweets (05,
17, 27) and User 2's tweets (06, 12, 29) will always be ordered
properly by time within each user even though the second digit is
random.

--
--
If you liked this email, you might also like:
Good article on technical aspects of lens variation
-- http://workstuff.tumblr.com/post/479306926
Cooking at home is different
-- http://www.aquick.org/blog/2009/10/15/cooking-at-home-is-different/
Bloom
-- http://www.flickr.com/photos/fields/4449638140/
fields: RT @smokingapples: Warning: Clicking this link might result in
uncontr...
--
** Custom development project broken? Contact me, I can help.
** Some of what I do: http://workstuff.tumblr.com/post/70505118/aboutworkstuff

[ http://www.morningside-analytics.com ] .. Latest Venture
[ http://www.confabb.com ]  Founder

--
To unsubscribe, reply using remove me as the subject.

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```Will you still be able to look at two relative IDs and tell which one
came first and which one came second?

To unsubscribe from this group, send email to
with the words REMOVE ME as the subject.

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

``` So I think we need to allow Twitter some leeway here.

I apologize if my tone came off badly; it was not intended. I've just
had bumpy rides using timestamps for coordination in distributed
systems (less cool ones than space flight), so this worried me a
little. In the end, whatever Twitter decides to do, I'll work with.

As far as occasional glitches are concerned, we have those now. Every
so often, we still get Fail Whales, 5xx errors, DDos attacks, etc.

The difference is that those errors are straightforwardly detectable
on the client side and can be handled more or less gracefully. Minor,
intermittent data issues (like the odd missing tweet) are less
straightforward to detect, but still trigger support emails. :)

-josh

To unsubscribe from this group, send email to
with the words REMOVE ME as the subject.

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```So, I guess for the since_id issue, it boils down to this question:

Regarding the since_id parameter, when you (Twitter) flip the switch
on the new ID format, will I (as a developer) have to change any of my
code in order for it to function the way it does now? This question
applies equally for both the Twitter API and the Search API.

Check One:

[ ] YES
[ ] NO

Taylor's previous response alluded to no (a good thing), but I
wasn't 100% assured.

To unsubscribe from this group, send email to
with the words REMOVE ME as the subject.

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```I hope you're right, but my app design depends on since_id, and before I
proceed further I want to be sure that I will not have to rebuild when this
new format comes in.

On 26 March 2010 21:09, Ray Krueger raykrue...@gmail.com wrote:

I would think that this would make no difference for since_id. The
purpose of since_id is for us to the API give me the data I need
that's happened since this id. Don't assume it's implemented as
select * from tweets were id  since_id. :)

On Mar 26, 4:01 pm, Michael Bleigh mble...@gmail.com wrote:
To those voicing concerns about since_id I believe the key word is
that they will no longer be *sequential*, something entirely different
from them no longer being *increasing*. Since ID is a core part of the
Twitter API that I very much doubt will be in jeopardy from this
change. Twitter devs feel free to back me up or refute me. :)

On Mar 26, 4:41 pm, Taylor Singletary taylorsinglet...@twitter.com
wrote:

Hi Developers,

It's no secret that Twitter is growing exponentially. The tweets keep
coming
with ever increasing velocity, thanks in large part to your great
applications.

Twitter has adapted to the increasing number of tweets in ways that
have
affected you in the past: We moved from 32 bit unsigned integers to
64-bit
unsigned integers for status IDs some time ago. You all weathered that
storm
with ease. The tweetapoclypse was averted, and the tweets kept flowing.

Now we're reaching the scalability limit of our current tweet ID
generation
scheme. Unlike the previous tweet ID migrations, the solution to the
current
issue is significantly different. However, in most cases the new
approach we
will take will not result in any noticeable differences to you the
developer

We are planning to replace our current sequential tweet ID generation
routine with a simple, more scalable solution. IDs will still be 64-bit
unsigned integers. However, this new solution is no longer guaranteed
to
generate sequential IDs.  Instead IDs will be derived based on time:
the
most significant bits being sourced from a timestamp and the least
significant bits will be effectively random.

Please don't depend on the exact format of the ID. As our
infrastructure
needs evolve, we might need to tweak the generation algorithm again.

If you've been trying to divine meaning from status IDs aside from
their
role as a primary key, you won't be able to anymore. Likewise for usage
of
IDs in mathematical operations -- for instance, subtracting two status
IDs
to determine the number of tweets in between will no longer be
possible.

For the majority of applications we think this scheme switch will be a
non-event. Before implementing these changes, we'd like to know if your
applications currently depend on the sequential nature of IDs. Do you
depend
on the density of the tweet sequence being constant?  Are you trying to
analyze the IDs as anything other than opaque, ordered identifiers?
Aside
for guaranteed sequential tweet ID ordering, what APIs can we provide
you to

Taylor Singletary

To unsubscribe from this group, send email to twitter-development-talk+
ME as the subject.

To unsubscribe from this group, send email to
with the words REMOVE ME as the subject.

```

### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```I am still a little unclear if we will be able to determine the correct
since_id to pass to the api by always looking for the largest tweet id we have
seen.

It seems if two messages are posted at very close to same time, they may not be
sequential since the bottom bits will be randomly generated and I will not be
able to safely just always use the largest id I have seen as the since_id??

Correct me if I am confusing myself please.

On Mar 26, 2010, at 5:33 PM, Taylor Singletary wrote:

A quick clarification for you all since there seems to be the most concern
around using since_id as a parameter:

since_id will work as well as it does today as a result of this change.

Also, a reminder that the actual integer format of the tweet IDs will not be
changing. They'll still be unsigned 64bit integers as they are today.

Taylor Singletary

On Fri, Mar 26, 2010 at 1:41 PM, Taylor Singletary
Hi Developers,

It's no secret that Twitter is growing exponentially. The tweets keep coming
with ever increasing velocity, thanks in large part to your great
applications.

Twitter has adapted to the increasing number of tweets in ways that have
affected you in the past: We moved from 32 bit unsigned integers to 64-bit
unsigned integers for status IDs some time ago. You all weathered that storm
with ease. The tweetapoclypse was averted, and the tweets kept flowing.

Now we're reaching the scalability limit of our current tweet ID generation
scheme. Unlike the previous tweet ID migrations, the solution to the current
issue is significantly different. However, in most cases the new approach we
will take will not result in any noticeable differences to you the developer

We are planning to replace our current sequential tweet ID generation routine
with a simple, more scalable solution. IDs will still be 64-bit unsigned
integers. However, this new solution is no longer guaranteed to generate
sequential IDs.  Instead IDs will be derived based on time: the most
significant bits being sourced from a timestamp and the least significant
bits will be effectively random.

Please don't depend on the exact format of the ID. As our infrastructure
needs evolve, we might need to tweak the generation algorithm again.

If you've been trying to divine meaning from status IDs aside from their role
as a primary key, you won't be able to anymore. Likewise for usage of IDs in
mathematical operations -- for instance, subtracting two status IDs to
determine the number of tweets in between will no longer be possible.

For the majority of applications we think this scheme switch will be a
non-event. Before implementing these changes, we'd like to know if your
applications currently depend on the sequential nature of IDs. Do you depend
on the density of the tweet sequence being constant?  Are you trying to
analyze the IDs as anything other than opaque, ordered identifiers? Aside for
guaranteed sequential tweet ID ordering, what APIs can we provide you to

Taylor Singletary

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### Re: [twitter-dev] Re: Upcoming changes to the way status IDs are sequenced

```Hi Taylor (et al.),

There are two reasons to think that, with the scheme you propose,
tweet ids will not necessarily be monotonically increasing.

Naveen hit the first:

It seems if two messages are posted at very close to same time, they may not
be sequential since the bottom bits will be randomly generated

There is another: Time synchronization is hard to always get right
(Einstein jokes aside). Clock skew happens for any number of reasons
-- sometimes ntpd sends time backwards when network i/o gets really
ugly, machine clocks wander, colos get out of sync, humans err, etc.
These are rare events, but they do happen, and they can cause
misalignment of clocks big enough for the odd tweet or two to fall
through.

Does missing the odd tweet or two matter? As for the tweet themselves:
Probably not. But if it gets noticed, it causes users / developers to
lose some amount of trust in their app / platform...and that matters a
lot and can also generate a lot of annoying support emails.

You wrote:

since_id will work as well as it does today as a result of this change.

Is that assuming monotonically increasing tweet ids? If not, would you
mind elaborating?

Having a universal counter is untenable, but having occasional,
undiagnosable, unreproducible glitches also sucks. :) Thinking out
loud, perhaps there is some middle ground -- a way to have generally
monotonically increasing ids globally, and guaranteed monotonically
increasing ids along some useful dimension, such as per user (this
doesn't play nicely e.g. w/ Cassandra, but it is still reasonably
scalable by other means). Not sure whether that would help folks or
not...

-josh

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