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https://issues.apache.org/jira/browse/FLINK-19710?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17244397#comment-17244397
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Brad Davis commented on FLINK-19710:
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The upstream PR has been merged. Is this issue just waiting on flink-side
testing to verify the fix?
> Fix performance regression to rebase FRocksDB with higher version RocksDB
> -------------------------------------------------------------------------
>
> Key: FLINK-19710
> URL: https://issues.apache.org/jira/browse/FLINK-19710
> Project: Flink
> Issue Type: Improvement
> Components: Runtime / State Backends
> Reporter: Yun Tang
> Assignee: Yun Tang
> Priority: Major
> Fix For: 1.13.0
>
>
> We planed to bump base rocksDB version from 5.17.2 to 6.11.x. However, we
> observed performance regression compared with 5.17.2 and 5.18.3 via our own
> flink-benchmarks, and reported to RocksDB community in
> [rocksdb#5774|https://github.com/facebook/rocksdb/issues/5774]. Since
> rocksDB-5.18.3 is a bit old for RocksDB community, and rocksDB built-in
> db_bench tool cannot easily reproduce this regression, we did not get any
> efficient help from RocksDB community.
> Since code freeze of Flink-release-1.12 is close, we have to figure it out by
> ourself. We try to use rocksDB built-in db_bench tool first to binary
> searching the 160 different commits between rocksDB 5.17.2 and 5.18.3.
> However, the performance regression is not so clear. And after using our own
> flink-benchmarks. We finally detect the commit which introduced the
> nearly-10% performance regression: [replaced __thread with thread_local
> keyword
> |https://github.com/facebook/rocksdb/commit/d6ec288703c8fc53b54be9e3e3f3ffd6a7487c63]
> .
> From existing knowledge, the performance regression of {{thread-local}} is
> known from [gcc-4.8 changes|https://gcc.gnu.org/gcc-4.8/changes.html#cxx] and
> become more serious in [dynamic modules usage
> |http://david-grs.github.io/tls_performance_overhead_cost_linux/] [[tls
> benchmark|https://testbit.eu/2015/thread-local-storage-benchmark]]]. That
> could explain why rocksDB built-in db_bench tool cannot reproduce this
> regression as it is complied in static mode by recommendation.
>
> We plan to fix this in our FRocksDB branch first to revert related changes.
> And from my current local experimental result, that revert proved to be
> effective to avoid that performance regression.
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