[jira] Commented: (CASSANDRA-2158) memtable_throughput_in_mb can not support sizes over 2.2 gigs because of an integer overflow.

["Jonathan Ellis (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-2158?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12994105#comment-12994105 ] 

Jonathan Ellis commented on CASSANDRA-2158:
-------------------------------------------

While you are correct, you almost certainly shouldn't have throughput set that high, because if you are tuning things correctly you will hit your operations count limit first for 99.9% of workloads.

> memtable_throughput_in_mb can not support sizes over 2.2 gigs because of an integer overflow.
> ---------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-2158
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-2158
>             Project: Cassandra
>          Issue Type: Bug
>    Affects Versions: 0.7.0
>            Reporter: Eddie
>
> If memtable_throughput_in_mb is set past 2.2 gigs, no errors are thrown.  However, as soon as data starts being written it is almost immediately being flushed.  Several hundred SSTables are created in minutes.  I am almost positive that the problem is that when memtable_throughput_in_mb is being converted into bytes the result is stored in an integer, which is overflowing.
> From memtable.java:
>     private final int THRESHOLD;
>     private final int THRESHOLD_COUNT;
> ...
> this.THRESHOLD = cfs.getMemtableThroughputInMB() * 1024 * 1024;
> this.THRESHOLD_COUNT = (int) (cfs.getMemtableOperationsInMillions() * 1024 * 1024);
> NOTE:
> I also think currentThroughput also needs to be changed from an int to a long.  I'm not sure if it is as simple as this or if this also is used in other places.

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