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
 



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Tyler Hobbs
DataStax