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From kurt greaves <k...@instaclustr.com>
Subject Re: Lightweight transaction in Multi DC
Date Sat, 09 Sep 2017 21:19:53 GMT
Yes it will "slow down" as more nodes need to be involved. Yes you will
need to use SERIAL for both reads and writes.

On 9 Sep. 2017 08:49, "Charulata Sharma (charshar)" <charshar@cisco.com>
wrote:

> Thanks for your reply. I understand that LOCAL_SERIAL is for within a DC ,
> will setting up SERIAL not slow down the operation?
>
> And should I set SERIAL for both read and write phase or just Read phase?
> This is becoming a big problem for us. It happens for a small percentage of
>
> data set but it happens daily because of the highly concurrent and random
> DC routing of the received events.
>
>
>
> We had a counter implementation prior to CAS, which used to fail most of
> the times. CAS provided a big relief but it is still not totally without
> errors.
>
> Would really appreciate the community’s feedback.
>
>
>
> Thanks,
>
> Charu
>
>
>
> *From: *vasu gunja <vasu.nosql@gmail.com>
> *Reply-To: *"user@cassandra.apache.org" <user@cassandra.apache.org>
> *Date: *Friday, September 8, 2017 at 1:56 PM
> *To: *"user@cassandra.apache.org" <user@cassandra.apache.org>
> *Subject: *Re: Lightweight transaction in Multi DC
>
>
>
> LOCAL_SERIAL is dc level, SERIAL checks for complete cluster level.
>
>
>
> On Fri, Sep 8, 2017 at 2:33 PM, Charulata Sharma (charshar) <
> charshar@cisco.com> wrote:
>
> Yes …it is with LOCAL_SERIAL. Should I be using SERIAL ?
>
>
>
> Thanks,
>
> Charu
>
>
>
> *From: *DuyHai Doan <doanduyhai@gmail.com>
> *Reply-To: *"user@cassandra.apache.org" <user@cassandra.apache.org>
> *Date: *Friday, September 8, 2017 at 12:30 PM
> *To: *"user@cassandra.apache.org" <user@cassandra.apache.org>
> *Subject: *Re: Lightweight transaction in Multi DC
>
>
>
> Are you using CAS with SERIAL consistency level for your multi-DC setup ?
>
>
>
> On Fri, Sep 8, 2017 at 9:27 PM, Charulata Sharma (charshar) <
> charshar@cisco.com> wrote:
>
> Hi,
>
>       We are facing a serious issue with CAS in a multi DC setup and I
> wanted to get some input on it from the forum.
>
>
>
> We have a Column family which stores counts for the number of events our
> application receives. When the counts reach a certain threshold,
>
> there is another process which kicks in. The issue that is happening is,
> sometimes when concurrent events come in 2 Data Centers, both the events
> read the same count
>
> and increment it to the same value which causes the next process to not
> kick in.
>
>
>
> When concurrent events come in the same DC, this does not happen, because
> in this case, the CAS explicitly fails for one of them.
>
> However, in case of Multiple DCs this is not happening. Has anyone faced a
> similar issue and is there any resolution to this?? I was unable to find
> any open Jira on this.
>
>
>
> Thanks,
>
> Charu
>
>
>
>
>
>
>
>
>

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