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Posted to issues@hbase.apache.org by "Lars Hofhansl (Commented) (JIRA)" <ji...@apache.org> on 2012/03/13 05:36:00 UTC
[jira] [Commented] (HBASE-5568) Multi concurrent flushcache() for
one region could cause data loss
[ https://issues.apache.org/jira/browse/HBASE-5568?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13228192#comment-13228192 ]
Lars Hofhansl commented on HBASE-5568:
--------------------------------------
Hi Chunhui. You patch only moves the synchronized block out of the try block. Could you explain why this fixes the issue?
> Multi concurrent flushcache() for one region could cause data loss
> ------------------------------------------------------------------
>
> Key: HBASE-5568
> URL: https://issues.apache.org/jira/browse/HBASE-5568
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Reporter: chunhui shen
> Assignee: chunhui shen
> Attachments: HBASE-5568.patch
>
>
> We could call HRegion#flushcache() concurrently now through HRegionServer#splitRegion or HRegionServer#flushRegion by HBaseAdmin.
> However, we find if HRegion#internalFlushcache() is called concurrently by multi thread, HRegion.memstoreSize will be calculated wrong.
> At the end of HRegion#internalFlushcache(), we will do this.addAndGetGlobalMemstoreSize(-flushsize), but the flushsize may not the actual memsize which flushed to hdfs. It cause HRegion.memstoreSize is negative and prevent next flush if we close this region.
> Logs in RS for region e9d827913a056e696c39bc569ea3
> 2012-03-11 16:31:36,690 DEBUG org.apache.hadoop.hbase.regionserver.HRegion: Started memstore flush for writetest1,,1331454657410.e9d827913a056e696c39bc569ea3
> f99f., current region memstore size 128.0m
> 2012-03-11 16:31:37,999 INFO org.apache.hadoop.hbase.regionserver.Store: Added hdfs://dw74.kgb.sqa.cm4:9700/hbase-func1/writetest1/e9d827913a056e696c39bc569e
> a3f99f/cf1/8162481165586107427, entries=153106, sequenceid=619316544, memsize=59.6m, filesize=31.2m
> 2012-03-11 16:31:38,830 DEBUG org.apache.hadoop.hbase.regionserver.HRegion: Started memstore flush for writetest1,,1331454657410.e9d827913a056e696c39bc569ea3
> f99f., current region memstore size 134.8m
> 2012-03-11 16:31:39,458 INFO org.apache.hadoop.hbase.regionserver.Store: Added hdfs://dw74.kgb.sqa.cm4:9700/hbase-func1/writetest1/e9d827913a056e696c39bc569e
> a3f99f/cf2/3425971951499794221, entries=230183, sequenceid=619316544, memsize=68.5m, filesize=26.6m
> 2012-03-11 16:31:39,459 INFO org.apache.hadoop.hbase.regionserver.HRegion: Finished memstore flush of ~128.1m for region writetest1,,1331454657410.e9d827913a
> 056e696c39bc569ea3f99f. in 2769ms, sequenceid=619316544, compaction requested=false
> 2012-03-11 16:31:39,459 DEBUG org.apache.hadoop.hbase.regionserver.HRegion: Started memstore flush for writetest1,,1331454657410.e9d827913a056e696c39bc569ea3
> f99f., current region memstore size 6.8m
> 2012-03-11 16:31:39,529 INFO org.apache.hadoop.hbase.regionserver.Store: Added hdfs://dw74.kgb.sqa.cm4:9700/hbase-func1/writetest1/e9d827913a056e696c39bc569e
> a3f99f/cf1/1811012969998104626, entries=8002, sequenceid=619332759, memsize=3.1m, filesize=1.6m
> 2012-03-11 16:31:39,640 INFO org.apache.hadoop.hbase.regionserver.Store: Added hdfs://dw74.kgb.sqa.cm4:9700/hbase-func1/writetest1/e9d827913a056e696c39bc569e
> a3f99f/cf2/770333473623552048, entries=12231, sequenceid=619332759, memsize=3.6m, filesize=1.4m
> 2012-03-11 16:31:39,641 INFO org.apache.hadoop.hbase.regionserver.HRegion: Finished memstore flush of ~134.8m for region writetest1,,1331454657410.e9d827913a
> 056e696c39bc569ea3f99f. in 811ms, sequenceid=619332759, compaction requested=true
> 2012-03-11 16:31:39,707 INFO org.apache.hadoop.hbase.regionserver.Store: Added hdfs://dw74.kgb.sqa.cm4:9700/hbase-func1/writetest1/e9d827913a056e696c39bc569e
> a3f99f/cf1/5656568849587368557, entries=119, sequenceid=619332979, memsize=47.4k, filesize=25.6k
> 2012-03-11 16:31:39,775 INFO org.apache.hadoop.hbase.regionserver.Store: Added hdfs://dw74.kgb.sqa.cm4:9700/hbase-func1/writetest1/e9d827913a056e696c39bc569e
> a3f99f/cf2/794343845650987521, entries=157, sequenceid=619332979, memsize=47.8k, filesize=19.3k
> 2012-03-11 16:31:39,777 INFO org.apache.hadoop.hbase.regionserver.HRegion: Finished memstore flush of ~6.8m for region writetest1,,1331454657410.e9d827913a05
> 6e696c39bc569ea3f99f. in 318ms, sequenceid=619332979, compaction requested=true
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