Hi Arko,
Never used that consistency level so far, but here is some information:
http://docs.datastax.com/en/cassandra/2.0/cassandra/dml/dml_tunable_consistency_c.html
Cassandra 2.0 uses the Paxos consensus protocol, which resembles 2-phase
> commit, to support linearizable consistency. All opera
On Tue, Mar 15, 2016 at 6:43 PM, Arko Provo Mukherjee <
arkoprovomukher...@gmail.com> wrote:
> I am designing a system where for a situation, I need to have SERIAL
> consistency during writes.
>
Be sure to understand the implications of :
https://issues.apache.org/jira/browse/CASSANDRA-9328
=Ro
Hello,
I am designing a system where for a situation, I need to have SERIAL
consistency during writes.
I understand that if the write was with QUORUM, a Read with QUORUM would
have fetched me the correct (most recent) data.
My question is what is the minimum consistency level required for read,
On Tue, Jun 30, 2015 at 11:16 AM, Tyler Hobbs wrote:
>
> Correct, if you get a WriteTimeout error, you don't know if any replicas
> have written the data or not. It's even possible that all replicas wrote
> the data but didn't respond to the coordinator in time. I suspect most
> users handle th
On Tue, Jun 30, 2015 at 12:27 PM, Anuj Wadehra
wrote:
> Agree Tyler. I think its our application problem. If client returns failed
> write in spite of retries, application must have a rollback mechanism to
> make sure old state is restored. Failed write may be because of the fact
> that CL was no
:"Tyler Hobbs"
Date:Tue, 30 Jun, 2015 at 10:42 pm
Subject:Re: Read Consistency
I think these scenarios are still possible even when we are writing at QUORUM
..if we have dropped mutations in our cluster..
It was very strange in our case ...We had RF=3 and READ/WRITE CL=QUORUM..we ha
Anuj Wadehra
wrote:
> Sorry for typo in your name Owen !!
>
> Anuj
>
> Sent from Yahoo Mail on Android
> <https://overview.mail.yahoo.com/mobile/?.src=Android>
> --
> *From*:"Anuj Wadehra"
> *Date*:Sun, 28 Jun, 2015 at 11:1
Sorry for typo in your name Owen !!
Anuj
Sent from Yahoo Mail on Android
From:"Anuj Wadehra"
Date:Sun, 28 Jun, 2015 at 11:11 pm
Subject:Re: Read Consistency
Agree Owem !! Response in both scenarios would depend on the 2 replicas chosen
for meeting QUORUM. But, the intent is
at in scenario 1, data would be returned and
that was my initial understanding..
Anuj
Sent from Yahoo Mail on Android
| From:"Anuj Wadehra"
Date:Wed, 24 Jun, 2015 at 12:15 am
Subject:Re: Read Consistency
| M more confused...Different responses. .Anyone who can explain with 100%
suri
ehra" >
> *Date*:Wed, 24 Jun, 2015 at 12:15 am
> *Subject*:Re: Read Consistency
>
> M more confused...Different responses. .Anyone who can explain with 100%
> surity ?
>
> Thanks
> Anuj
>
>
> Sent from Yahoo Mail on Android
> <https://overview.mail.yahoo.c
Thanks..So all of us agree that in scenario 1, data would be returned and that
was my initial understanding..
Anuj
Sent from Yahoo Mail on Android
From:"Anuj Wadehra"
Date:Wed, 24 Jun, 2015 at 12:15 am
Subject:Re: Read Consistency
M more confused...Different responses. .Anyo
M more confused...Different responses. .Anyone who can explain with 100% surity
?
Thanks
Anuj
Sent from Yahoo Mail on Android
From:"arun sirimalla"
Date:Wed, 24 Jun, 2015 at 12:00 am
Subject:Re: Read Consistency
Thanks good to know that.
On Tue, Jun 23, 2015 at 11:27
t;> Why would it fail and with what Thrift error? What if the data didnt
>>>> exist on any of the nodes..query wont fail if doesnt find data..
>>>>
>>>> Not convinced..
>>>>
>>>> Sent from Yahoo Mail on Android
>>>> <https://overv
Not convinced..
>>>
>>> Sent from Yahoo Mail on Android
>>> <https://overview.mail.yahoo.com/mobile/?.src=Android>
>>> --
>>> *From*:"arun sirimalla"
>>> *Date*:Tue, 23 Jun, 2015 at 11:39 pm
>>> *Subject*:Re: Read Consistency
>
ail if doesnt find data..
>>
>> Not convinced..
>>
>> Sent from Yahoo Mail on Android
>> <https://overview.mail.yahoo.com/mobile/?.src=Android>
>> --
>> *From*:"arun sirimalla"
>> *Date*:Tue, 23 Jun, 2015 at 11:
t find data..
>>
>> Not convinced..
>>
>> Sent from Yahoo Mail on Android
>> <https://overview.mail.yahoo.com/mobile/?.src=Android>
>> --
>> *From*:"arun sirimalla"
>> *Date*:Tue, 23 Jun, 2015 at 11:39 pm
&
if the data didnt exist
> on any of the nodes..query wont fail if doesnt find data..
>
> Not convinced..
>
> Sent from Yahoo Mail on Android
> <https://overview.mail.yahoo.com/mobile/?.src=Android>
> --
> *From*:"arun sirimalla"
&
Date*:Tue, 23 Jun, 2015 at 11:39 pm
> *Subject*:Re: Read Consistency
>
> Scenario 1: Read query is fired for a key, data is found on one node and
> not found on other two nodes who are responsible for the token
> corresponding to key.
>
> You read query will fail, as it expects to
Why would it fail and with what Thrift error? What if the data didnt exist on
any of the nodes..query wont fail if doesnt find data..
Not convinced..
Sent from Yahoo Mail on Android
From:"arun sirimalla"
Date:Tue, 23 Jun, 2015 at 11:39 pm
Subject:Re: Read Consistency
Scenario 1:
Scenario 1: Read query is fired for a key, data is found on one node and
not found on other two nodes who are responsible for the token
corresponding to key.
You read query will fail, as it expects to receive data from 2 nodes with
RF=3
Scenario 2: Read query is fired and all 3 replicas have dif
Hi,
Need to validate my understanding..
RF=3 , Read CL = Quorum
What would be returned to the client in following scenarios:
Scenario 1: Read query is fired for a key, data is found on one node and not
found on other two nodes who are responsible for the token corresponding to key.
Optio
the same value. We use QUORUM writes (will
be LOCAL_QUORUM as soon as we configure server to be DC aware), and that is
fine.
The point being, I wonder if there is something between ONE and QUORUM read
consistency level that I could specify in my situation to return as soon as any
node retu
Here some links related do C* and clock synchronization:
http://www.datastax.com/dev/blog/why-cassandra-doesnt-need-vector-clocks
http://ria101.wordpress.com/2011/02/08/cassandra-the-importance-of-system-clocks-avoiding-oom-and-how-to-escape-oom-meltdown/
2013/9/11 Jimmy Lin
> hi,
> I have
hi,
I have few question around the area how Cassandra use record's timestamp to
determine which one to return from its replicated nodes ...
-
A record's timestamp is determined by the Cassandra server node's system
timestamp when the request arrive the server and NOT by the client
timestamp who ma
Dan
From: Anthony Wilcox [mailto:peacepatr...@hotmail.com]
Sent: October-07-11 9:33
To: user@cassandra.apache.org
Subject: RE: Immutable CFs and read consistency
The last sentence should have been "In other words, does R apply also to
(possibly failed) read attempts or only to successful reads?&q
The last sentence should have been "In other words, does R apply also to
(possibly failed) read attempts or only to successful reads?"
Anthony
From: peacepatr...@hotmail.com
To: user@cassandra.apache.org
Subject: Immutable CFs and read consistency
Date: Fri, 7 Oct 2011 06:2
We have a Column Family that is immutable (no updates after the first write).
Suppose we use RF=2 and W=1. Do we still need R=2, so that R+W>RF? Or is it
sufficient to have R=1? My guess is yes, R=1 is sufficient since if it reads a
row, the row has to be correct: it can't get stale data.
again,
>
> Stephen
>
>
> From: Edward Capriolo [mailto:edlinuxg...@gmail.com]
> Sent: 18 August 2011 14:14
> To: user@cassandra.apache.org
> Subject: Re: A few questions on row caching and read consistency ONE
>
>
>
> On Thu, Aug 18, 2011 at 5:01 AM, St
> *From:* Edward Capriolo [mailto:edlinuxg...@gmail.com]
> *Sent:* 18 August 2011 14:14
> *To:* user@cassandra.apache.org
> *Subject:* Re: A few questions on row caching and read consistency ONE
>
>
>
>
>
> On Thu, Aug 18, 2011 at 5:01 AM, Stephen Henderson <
>
esults if they're
not too company-specific.
Thanks again,
Stephen
From: Edward Capriolo [mailto:edlinuxg...@gmail.com]
Sent: 18 August 2011 14:14
To: user@cassandra.apache.org
Subject: Re: A few questions on row caching and read consistency ONE
On Thu, Aug 18, 2011 at 5:01 AM, Stephen Henderson
m
ssandra
> and would rather stick with what we know if it can work).
>
> If anyone could help answer/clarify the following questions it would be a
> great help (all assume that row-caching is enabled for the column family).
>
> Q. If we're using read consistency ONE does the r
> Q. If we're using read consistency ONE does the read request get sent to all
> nodes in the replica set and the first to reply is returned (i.e. all replica
> nodes will then have that row in their cache), OR does the request only get
> sent to a single node in the replica
e a great
help (all assume that row-caching is enabled for the column family).
Q. If we're using read consistency ONE does the read request get sent to all
nodes in the replica set and the first to reply is returned (i.e. all replica
nodes will then have that row in their cache), OR does
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