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https://issues.apache.org/jira/browse/HBASE-19358?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yu Li reopened HBASE-19358:
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Reopening since this is not committed to branch-2 yet and the branch-2 v2 patch
cannot apply cleanly on latest code base thus requires refactor. [~tianjingyun]
please take a look, thanks.
And please correct the branch-2 patch name since now it's called
"HBASE-18619-branch-2-v2"...
> Improve the stability of splitting log when do fail over
> --------------------------------------------------------
>
> Key: HBASE-19358
> URL: https://issues.apache.org/jira/browse/HBASE-19358
> Project: HBase
> Issue Type: Improvement
> Components: MTTR
> Affects Versions: 0.98.24
> Reporter: Jingyun Tian
> Assignee: Jingyun Tian
> Fix For: 2.0.0, 3.0.0, 1.4.1, 1.5.0
>
> Attachments: HBASE-18619-branch-2-v2.patch,
> HBASE-18619-branch-2-v2.patch, HBASE-18619-branch-2.patch,
> HBASE-19358-branch-1-v2.patch, HBASE-19358-branch-1-v3.patch,
> HBASE-19358-branch-1.patch, HBASE-19358-v1.patch, HBASE-19358-v4.patch,
> HBASE-19358-v5.patch, HBASE-19358-v6.patch, HBASE-19358-v7.patch,
> HBASE-19358-v8.patch, HBASE-19358.patch, split-1-log.png,
> split-logic-new.jpg, split-logic-old.jpg, split-table.png,
> split_test_result.png
>
>
> The way we splitting log now is like the following figure:
> !https://issues.apache.org/jira/secure/attachment/12904506/split-logic-old.jpg!
> The problem is the OutputSink will write the recovered edits during splitting
> log, which means it will create one WriterAndPath for each region and retain
> it until the end. If the cluster is small and the number of regions per rs is
> large, it will create too many HDFS streams at the same time. Then it is
> prone to failure since each datanode need to handle too many streams.
> Thus I come up with a new way to split log.
> !https://issues.apache.org/jira/secure/attachment/12904507/split-logic-new.jpg!
> We try to cache all the recovered edits, but if it exceeds the MaxHeapUsage,
> we will pick the largest EntryBuffer and write it to a file (close the writer
> after finish). Then after we read all entries into memory, we will start a
> writeAndCloseThreadPool, it starts a certain number of threads to write all
> buffers to files. Thus it will not create HDFS streams more than
> *_hbase.regionserver.hlog.splitlog.writer.threads_* we set.
> The biggest benefit is we can control the number of streams we create during
> splitting log,
> it will not exceeds *_hbase.regionserver.wal.max.splitters *
> hbase.regionserver.hlog.splitlog.writer.threads_*, but before it is
> *_hbase.regionserver.wal.max.splitters * the number of region the hlog
> contains_*.
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