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 ?