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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: Counters != Counts
Date Fri, 16 Dec 2011 09:29:48 GMT
Can we have a hope that counters will be replayed as safely as a classical
data someday ? Do someone still work on jiras like
issues.apache.org/jira/browse/CASSANDRA-2495 ? I thought that replaying a
write from the client didn't lead to over-counts contrary to the internal
cassandra replay from commitlog.

I just made a new connection pool with retries / 2 and timeouts * 4. I hope
it will improve the accuracy of my counters.

Anyways, thank you for answering that fast.

Alain

2011/12/16 Tyler Hobbs <tyler@datastax.com>

> Probably quite a few of them are coming from automatic retries by
> phpcassa.  When working with counters, I recommend minimizing retries
> and/or increasing timeouts.  Usually this means you want to use a separate
> connection pool with different settings just for counters.
>
> By the way, this advice applies to other clients as well.
>
>
> On Wed, Dec 14, 2011 at 10:29 AM, Alain RODRIGUEZ <arodrime@gmail.com>wrote:
>
>> Hi everybody.
>>
>> I'm using a lot of counters to make statistics on a 4 nodes cluster (ec2
>> m1.small) with phpcassa (cassandra v1.0.2).
>>
>> I store some events and increment counters at the same time.
>>
>> Counters give me over-counts compared with the count of every
>> corresponding events.
>>
>> I sure that my non-counters counts are good.
>>
>> I'm not sure why these over-counts happen, but I heard that recovering
>> from commitlogs can produce this.
>> I have some timeouts on phpcassa which are written in my apache logs
>> while a compaction is running. However I am always able to write at Quorum,
>> so I guess I shouldn't have to recover from cassandra commitlogs.
>>
>> Where can these over-counts come from ?
>>
>> Alain
>>
>>
>
>
>
> --
> Tyler Hobbs
> DataStax <http://datastax.com/>
>
>

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