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From "Jonathan Ellis (Commented) (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-3741) OOMs because delete operations are not accounted
Date Fri, 13 Jan 2012 18:46:39 GMT


Jonathan Ellis commented on CASSANDRA-3741:

Thanks, Vitalii!

Unfortunately we can't use that patch as is because adding ops * 20 in there is going to throw
off the size calculation for other workloads.

Note that the "throughput" size for a deletion is NOT zero (see Column.size implementation).
 It sounds like you abruptly changed your workload from doing a bunch of larger inserts, then
hit it with a ton of deletes all at once and OOMed before it was able to update its liveRatio

So the real problem is that if you change workloads dramatically enough, Cassandra's estimates
can be off.
> OOMs because delete operations are not accounted
> ------------------------------------------------
>                 Key: CASSANDRA-3741
>                 URL:
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 1.1
>         Environment: FreeBSD
>            Reporter: Vitalii Tymchyshyn
> Currently we are moving to new data format where new format is written into new CFs and
old one is deleted key-by-key. 
> I have started getting OOMs and found out that delete operations are not accounted and
so, column families are not flushed (changed == 0 with delete only operations) by storage
> This is pull request that fixed this problem for me:

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