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From "Anoop Sam John (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-17343) Make Compacting Memstore default in 2.0 with BASIC as the default type
Date Tue, 25 Apr 2017 16:45:05 GMT

    [ https://issues.apache.org/jira/browse/HBASE-17343?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15983227#comment-15983227
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Anoop Sam John commented on HBASE-17343:
----------------------------------------

Did some PE perf testing with different value size (1K which is def in PE, 500 bytes, 100
bytes)..   
When value size is lesser, the gain from Compaction is more..  Even on bigger sized cells
case, there is no significant degrade.
Also I did test along with off heap memstore feature.. The gain is more when off heap also
in place. (This is what my thinking from day one and it comes correct as per the tests)..
 Off heap + Compacting Memstore comes as the best performance.
All tests use G1GC. I also did test with global memstore size as 42% as well as 60%.  In case
of 42%, the Initial Heap Occupancy Percentage (IHOP) is 50% where as in next case it is 65%.
 In the second case, some times I got long GC pause so that master thinks RS is died. 1 out
of 3 times I get this.  In case of 50% IHOP, this seems not coming.  Remember in all these
tests MSLAB is ON (which is the default behave).
I also did test with MSLAB off.   Seems this case is better performing than MSLAB ON cases.
 Specially when the cell size is smaller. In those , I could not reproduce the long GC pause.

I have a code level comment, (will say abt that in another comment) and a fix there avoided
the long GC issue in any case.. 

MSLAB ON vs OFF I tested specifically and seems when we have higher global memstore size %
and IHOP, the impact is more (MSLAB ON is lesser performing). When the IHOP is set to be 50%
(This defaults to 45%) , MSLAB ON is having bit better performance (Though not too much of
diff).    With G1GC, we have to check whether we should advice to turn off MSLAB..  Any way
off heap memstore is implemented using off heap MSLAB pool.. So as such it is useful only.
As I said, off heap memstore is better performing than on heap counter part and in memory
compaction there makes things even better.

Did not make a perf graphs.. Will be coming up with that soon (in a day or 2)

> Make Compacting Memstore default in 2.0 with BASIC as the default type
> ----------------------------------------------------------------------
>
>                 Key: HBASE-17343
>                 URL: https://issues.apache.org/jira/browse/HBASE-17343
>             Project: HBase
>          Issue Type: Bug
>    Affects Versions: 2.0.0
>            Reporter: ramkrishna.s.vasudevan
>            Priority: Blocker
>             Fix For: 2.0.0
>
>         Attachments: HBASE-17343-V01.patch, HBASE-17343-V02.patch, HBASE-17343-V04.patch
>
>
> FYI [~anastas], [~eshcar] and [~ebortnik].



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