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https://issues.apache.org/jira/browse/HBASE-16417?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15904833#comment-15904833
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Anoop Sam John commented on HBASE-16417:
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Thanks for the nice perf tests and summary.
bq. HBASE_OPTS="-XX:+UseG1GC -XX:MaxGCPauseMillis=200
-XX:InitiatingHeapOccupancyPercent=60 -XX:G1HeapWastePercent=20
-XX:G1MixedGCCountTarget=8
I have a concern here. Using G1GC with InitiatingHeapOccupancyPercent(IHOP) of
60%. But in mixed workload, the working size itself is 80% (40% for Memstore
and 40% for BC). The GC impact will be more here..Can we have a test with
better GC tuning? Already we have load on GC and the merge, as it needs more
memory to work for the index copy (for merge), we might not see better results?
Ya reading from more Segments, instead of 1, can be one reason for the 95th
percentile perf degrade.
bq.Since previous experiments show consistently weaker performance with on-heap
mslabs we focus on running experiments with no chunks pool​ and no mslabs
Above said GC config and HBase config can be an issue here also? The impact of
this will be more when u work with MSLAB as MSLAB chunks will be always fixed
to process once created. With G1GC we should revist our defaults for BC and
Memstore size. We need to keep the sum of both to be under the IHOP. Or else
up IHOP. Then the advantage of G1GC itself is lost. The default for IHOP is 45%
bq.We run in synchronous and asynch WAL modes.
How can the perf for CompactingMemstore be affected by WAL type? Any reason why
u did test for both types? Any analysis here?
bq.Batching writes at the client side; buffer size is 10KB
Seems small buffer size. Any specific consideration in this selection? Just
asking
Still not sure how the Eager mode reduced the #WAL files.
> In-Memory MemStore Policy for Flattening and Compactions
> --------------------------------------------------------
>
> Key: HBASE-16417
> URL: https://issues.apache.org/jira/browse/HBASE-16417
> Project: HBase
> Issue Type: Sub-task
> Reporter: Anastasia Braginsky
> Assignee: Eshcar Hillel
> Fix For: 2.0.0
>
> Attachments: HBASE-16417-benchmarkresults-20161101.pdf,
> HBASE-16417-benchmarkresults-20161110.pdf,
> HBASE-16417-benchmarkresults-20161123.pdf,
> HBASE-16417-benchmarkresults-20161205.pdf,
> HBASE-16417-benchmarkresults-20170309.pdf
>
>
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