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From "Lars Hofhansl (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HBASE-10117) Avoid synchronization in HRegionScannerImpl.isFilterDone
Date Tue, 10 Dec 2013 05:10:08 GMT
Lars Hofhansl created HBASE-10117:
-------------------------------------

             Summary: Avoid synchronization in HRegionScannerImpl.isFilterDone
                 Key: HBASE-10117
                 URL: https://issues.apache.org/jira/browse/HBASE-10117
             Project: HBase
          Issue Type: Bug
          Components: Performance
            Reporter: Lars Hofhansl
             Fix For: 0.94.15, 0.96.2, 0.98.1


A while ago I introduced HRegoinScannerImpl.nextRaw() to allow coprocessors and scanners with
caching > 1 to avoid repeated synchronization during the scanning (which puts up memory
fences, which in turns slows things down on multi core machines).

Looking at the code again I see that isFilterDone() is called from nextRaw() and isFilterDone()
is synchronized. isFilterDone() is only called from two places. The other place is rare in
RegionServer.next() when we're bypassing at the request of a coprocessor. We can add synchronization
there.




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