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https://issues.apache.org/jira/browse/HBASE-19357?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16281328#comment-16281328
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Anoop Sam John commented on HBASE-19357:
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bq. It is years since we did heap vs BC compare.
Did tests 2 weeks back also based on Alpha-4 release. This is again a single
node test only comparing the on heap LRU cache (old L1) vs off heap Bucket
Cache (Old L2)
On heap Test
------------------
Single server with 42 GB heap size. 60% cache size ie. 25 GB. Using G1GC
with 65% as Initial Heap Occupancy Factor.
Off heap Test
------------------
Single server with 17 GB heap size and 25 GB off heap Bucket cache size. Here
it is combined cache any way with just 20% as the L1 cache size. Again GC
tuning is same
PE tests with single CF and single column and 1K value size per cell(PE
defaults). Pushed ~25GB data. Warming up cache before the read tests so as to
put whole data in cache.
Random row read test with 100 threads.
Result
On heap test gives a QPS of 421940.9 whereas off heap gives a QPS of 476190.5.
So for 100 threads load we have a QPS gain of 12.8%.
> Bucket cache no longer L2 for LRU cache
> ---------------------------------------
>
> Key: HBASE-19357
> URL: https://issues.apache.org/jira/browse/HBASE-19357
> Project: HBase
> Issue Type: Sub-task
> Reporter: Anoop Sam John
> Assignee: Anoop Sam John
> Fix For: 2.0.0-beta-1
>
> Attachments: HBASE-19357.patch, HBASE-19357.patch,
> HBASE-19357_V2.patch, HBASE-19357_V3.patch, HBASE-19357_V3.patch
>
>
> When Bucket cache is used, by default we dont configure it as an L2 cache
> alone. The default setting is combined mode ON where the data blocks to
> Bucket cache and index/bloom blocks go to LRU cache. But there is a way to
> turn this off and make LRU as L1 and Bucket cache as a victim handler for L1.
> It will be just L2.
> After the off heap read path optimization Bucket cache is no longer slower
> compared to L1. We have test results on data sizes from 12 GB. The Alibaba
> use case was also with 12 GB and they have observed a ~30% QPS improve over
> the LRU cache.
> This issue is to remove the option for combined mode = false. So when Bucket
> cache is in use, data blocks will go to it only and LRU will get only index
> /meta/bloom blocks. Bucket cache will no longer be configured as a victim
> handler for LRU.
> Note : WHen external cache is in use, there only the L1 L2 thing comes. LRU
> will be L1 and external cache act as its L2. That make full sense.
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