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Posted to commits@cassandra.apache.org by "Vijay (JIRA)" <ji...@apache.org> on 2015/01/20 19:03:35 UTC
[jira] [Assigned] (CASSANDRA-6544) Reduce GC activity during
compaction
[ https://issues.apache.org/jira/browse/CASSANDRA-6544?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Vijay reassigned CASSANDRA-6544:
--------------------------------
Assignee: (was: Vijay)
> Reduce GC activity during compaction
> ------------------------------------
>
> Key: CASSANDRA-6544
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6544
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Vijay
> Labels: compaction
> Fix For: 2.1.3
>
>
> We are noticing increase in P99 while the compactions are running at full stream. Most of it is because of the increased GC activity (followed by full GC).
> The obvious solution/work around is to throttle the compactions, but with SSD's we can get more disk bandwidth for reads and compactions.
> It will be nice to move the compaction object allocations off heap. First thing to do might be create a Offheap Slab allocator with the size as the compaction in memory size and recycle it.
> Also we might want to make it configurable so folks can disable it when they don't have off-heap memory to reserve.
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