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https://issues.apache.org/jira/browse/HBASE-5349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13846947#comment-13846947
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Andrew Purtell edited comment on HBASE-5349 at 12/13/13 12:07 AM:
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bq. seems if we tweak block cache dynamically, it's more prone to trigger a gc
that moment, right?
This is largely out of our control, until and unless the JVM exposes some knobs
for GC and early warning signals. Between memstore and blockcache we can't just
look at JVM heap occupancy, we will be keeping it pretty full.
We can provide a null tuner to remove this as a factor when getting to the
bottom of excessive GCs though.
was (Author: apurtell):
bq. seems if we tweak block cache dynamically, it's more prone to trigger a gc
that moment, right?
This is largely out of our control, until and unless the JVM exposes some knobs
for GC and early warning signals. Between memstore and blockcache we can't just
look at occupancy.
We can provide a null tuner to remove this as a factor when getting to the
bottom of excessive GCs though.
> Automagically tweak global memstore and block cache sizes based on workload
> ---------------------------------------------------------------------------
>
> Key: HBASE-5349
> URL: https://issues.apache.org/jira/browse/HBASE-5349
> Project: HBase
> Issue Type: Improvement
> Affects Versions: 0.92.0
> Reporter: Jean-Daniel Cryans
> Assignee: Anoop Sam John
> Fix For: 0.99.0
>
> Attachments: HBASE-5349_V2.patch, HBASE-5349_V3.patch,
> HBASE-5349_V4.patch, HBASE-5349_V5.patch, WIP_HBASE-5349.patch
>
>
> Hypertable does a neat thing where it changes the size given to the CellCache
> (our MemStores) and Block Cache based on the workload. If you need an image,
> scroll down at the bottom of this link:
> http://www.hypertable.com/documentation/architecture/
> That'd be one less thing to configure.
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