BTW, when testing this branch, we found some performance issues about
HDFS Client:
1. we reduced the DFS client's heap allocation from 45% to 27%
in HDFS-14535 [1];
2. we also increased get throughput by 17.8% in disabled block cache case
in HDFS-14541[2].
In theory, it should also helps a lot (especially p99/p999) even if RS
has a high cacheHitRatio.
I think the next HDFS 2.8 release will include those patches, they're very
good points for our
HBase performance.
[1]. https://issues.apache.org/jira/browse/HDFS-14535
[2].
https://issues.apache.org/jira/browse/HDFS-14541?focusedCommentId=16866472&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16866472
Thanks.
On Tue, Jun 18, 2019 at 12:05 PM OpenInx <open...@gmail.com> wrote:
> The HBASE-21879 has lots of changes: 123 files changed, 5833
> insertions(+), 3015 deletions(-).
> Currently we developed this issue based on master branch, and expect to
> release it in future HBase3.x.
> Of course, if branch-2 want this feature we can do the backport, should
> have some conflicts now but I
> don't think it would be hard to fix because I believe the branch-2
> shouldn't have so much diff with master now
> (at least in read path).
> The first priority thing for now, I think it would be merging the
> HBASE-21879 branch to master branch
> before diverging. After that, I can do the backport.
>
> Thanks for your suggestion, Guanghao !
>
>
>
> On Tue, Jun 18, 2019 at 11:39 AM Guanghao Zhang <zghao...@gmail.com>
> wrote:
>
>> This is a improvement not a new feature? So backport to branch-2, too?
>>
>> OpenInx <open...@gmail.com> 于2019年6月17日周一 下午2:45写道：
>>
>> > Dear HBase dev:
>> >
>> > In HBASE-21879[1], we redesigned the offheap read path: read the
>> HFileBlock
>> > from HDFS to pooled offheap
>> > ByteBuffers directly, while before HBASE-21879 we just read the
>> HFileBlock
>> > to heap which would still lead
>> > to high GC pressure.
>> >
>> > After few months of development and testing, all subtasks have been
>> > resovled now except the HBASE-21946[2]
>> > (It depends on HDFS-14483[3] and our HDFS teams are working on this, we
>> > expect the HDFS-14483 to be included
>> > in hadoop 2.8.6 and after that the HBASE-21946 will get resolved). we
>> think
>> > the feature is stable enough now and it's
>> > time to merge branch HBASE-21879 back to master now.
>> >
>> > We have designed 3 test cases to prove the performance improvment with
>> > HBASE-21879:
>> > 1. Disabled BlockCache, which means the cacheHitRatio is 0%;
>> > 2. CacheHitRatio~65%;
>> > 3. CachehHitRatio~100%;
>> >
>> > In our performance results[4], we can see that: the case#1 have an great
>> > performance improvement
>> > (
>> > *throughput increased about 17%, heap allocation decreased about 95%,
>> Young
>> > generaion size decreased about 81.7%*), that's because after HBASE-21879
>> > all reads will allocate from pooled offheap bytebuffers
>> > and almost no heap allocation, while before HBASE-21879 the read path
>> will
>> > create so many heap allocations.
>> > On the other hand, from the testing results of case#2 and case#3 we can
>> > also see that:
>> >
>> > *As the cacheHitRatioincreasing, the difference between
>> before-HBASE-21879
>> > and after-HBASE-21879 will decrease, when cacheHitRatio is 100%, they
>> > almost have no much difference in both throughput and latency.*
>> >
>> > For more details please see the document[4]. Thanks
>> > Anoop/Ram/DuoZhang/Stack/GuanghaoZhang very much
>> > for your meticulous work (Suggession, discussion, patch reviewing, doc
>> > reviewing etc).
>> >
>> > Please vote
>> >
>> > [] +1
>> > [] +0/-0
>> > [] -1 Do not merge the branch back because...
>> >
>> > Thanks. Any suggestions are welcomed.
>> >
>> > [1] https://issues.apache.org/jira/browse/HBASE-21879
>> > [2] https://issues.apache.org/jira/browse/HBASE-21946
>> > [3] https://issues.apache.org/jira/browse/HDFS-14483
>> > [4]
>> >
>> >
>> https://docs.google.com/document/d/1xSy9axGxafoH-Qc17zbD2Bd--rWjjI00xTWQZ8ZwI_E
>> >
>>
>
