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https://issues.apache.org/jira/browse/HBASE-8894?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13798998#comment-13798998
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Liang Xie commented on HBASE-8894:
----------------------------------
I had run an apple to apple perf test this afternoon, shows this l2 cache is
worse than orignial bucket cache. In my 100% read only scenario, with same
Xmx/Directmemory/(l2).bucketcache size setting, the response time and us/sys
cpu% were very stable in bucket cache, but very unstable on l2 cache, more
worse things is in my scenario, there's 0 fgc for bucket cache, but lots of fgc
be observed for l2 cache, my explaination is the data block could goto heap's
lru block cache, that makes heap fragment happened again, and then, the fgc's
cost beat all the earnings of l2 cache (like get rid of　deserialization)
> Forward port compressed l2 cache from 0.89fb
> --------------------------------------------
>
> Key: HBASE-8894
> URL: https://issues.apache.org/jira/browse/HBASE-8894
> Project: HBase
> Issue Type: New Feature
> Reporter: stack
> Assignee: Liang Xie
> Priority: Critical
> Attachments: HBASE-8894-0.94-v1.txt, HBASE-8894-0.94-v2.txt
>
>
> Forward port Alex's improvement on hbase-7407 from 0.89-fb branch:
> {code}
> 1 r1492797 | liyin | 2013-06-13 11:18:20 -0700 (Thu, 13 Jun 2013) | 43 lines
> 2
> 3 [master] Implements a secondary compressed cache (L2 cache)
> 4
> 5 Author: avf
> 6
> 7 Summary:
> 8 This revision implements compressed and encoded second-level cache with
> off-heap
> 9 (and optionally on-heap) storage and a bucket-allocator based on
> HBASE-7404.
> 10
> 11 BucketCache from HBASE-7404 is extensively modified to:
> 12
> 13 * Only handle byte arrays (i.e., no more serialization/deserialization
> within)
> 14 * Remove persistence support for the time being
> 15 * Keep an index of hfilename to blocks for efficient eviction on close
> 16
> 17 A new interface (L2Cache) is introduced in order to separate it from the
> current
> 18 implementation. The L2 cache is then integrated into the classes that
> handle
> 19 reading from and writing to HFiles to allow cache-on-write as well as
> 20 cache-on-read. Metrics for the L2 cache are integrated into
> RegionServerMetrics
> 21 much in the same fashion as metrics for the existing (L2) BlockCache.
> 22
> 23 Additionally, CacheConfig class is re-refactored to configure the L2
> cache,
> 24 replace multile constructors with a Builder, as well as replace static
> methods
> 25 for instantiating the caches with abstract factories (with singleton
> 26 implementations for both the existing LruBlockCache and the newly
> introduced
> 27 BucketCache based L2 cache)
> 28
> 29 Test Plan:
> 30 1) Additional unit tests
> 31 2) Stress test on a single devserver
> 32 3) Test on a single-node in shadow cluster
> 33 4) Test on a whole shadow cluster
> 34
> 35 Revert Plan:
> 36
> 37 Reviewers: liyintang, aaiyer, rshroff, manukranthk, adela
> 38
> 39 Reviewed By: liyintang
> 40
> 41 CC: gqchen, hbase-eng@
> 42
> 43 Differential Revision: https://phabricator.fb.com/D837264
> 44
> 45 Task ID: 2325295
> 7 ------------------------------------------------------------------------
> 6 r1492340 | liyin | 2013-06-12 11:36:03 -0700 (Wed, 12 Jun 2013) | 21 lines
> {code}
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