Jingyun Tian created HBASE-19358:
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Summary: 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
Now the way we split log is like the following figure:
!previous-logic.png|thumbnail!
The problem is the OutputSink will write the recovered edits during splitting
log, which means it will create one WriterAndPath for each region. 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.
!attachment-name.jpg|thumbnail!
We cached the recovered edits unless exceeds the memory limits we set or reach
the end, then we have a thread pool to do the rest things: write them to files
and move to the destination.
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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