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https://issues.apache.org/jira/browse/HBASE-4241?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13090792#comment-13090792
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jirapos...@reviews.apache.org commented on HBASE-4241:
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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/1650/
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(Updated 2011-08-25 05:38:13.482663)
Review request for hbase, Ted Yu, Michael Stack, and Jonathan Gray.
Summary
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This avoids flushing row versions to disk that are known to be GC'd by the next
compaction anyway.
This covers two scenarios:
1. maxVersions=N and we find at least N versions in the memstore. We can safely
avoid flushing any further versions to disk.
2. similarly minVersions=N and we find at least N versions in the memstore. Now
we can safely avoid flushing any further *expired* versions to disk.
This changes the Store flush to use the same mechanism that used for
compactions.
I borrowed some code from the tests and refactored the test code to use a new
utility class that wraps a sorted collection and then behaves like
KeyValueScanner. The same class is used to create scanner over the memstore's
snapshot.
This addresses bug HBASE-4241.
https://issues.apache.org/jira/browse/HBASE-4241
Diffs (updated)
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http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/Store.java
1161347
http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/util/CollectionBackedScanner.java
PRE-CREATION
http://svn.apache.org/repos/asf/hbase/trunk/src/test/java/org/apache/hadoop/hbase/regionserver/KeyValueScanFixture.java
1161347
http://svn.apache.org/repos/asf/hbase/trunk/src/test/java/org/apache/hadoop/hbase/regionserver/TestKeyValueHeap.java
1161347
http://svn.apache.org/repos/asf/hbase/trunk/src/test/java/org/apache/hadoop/hbase/regionserver/TestKeyValueScanFixture.java
1161347
http://svn.apache.org/repos/asf/hbase/trunk/src/test/java/org/apache/hadoop/hbase/regionserver/TestMinVersions.java
1161347
http://svn.apache.org/repos/asf/hbase/trunk/src/test/java/org/apache/hadoop/hbase/regionserver/TestStore.java
1161347
Diff: https://reviews.apache.org/r/1650/diff
Testing
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Ran all tests. TestHTablePool and TestDistributedLogSplitting error out (with
or without my change).
I had to change three tests that incorrectly relied on old rows hanging around
after a flush (or were otherwise incorrect).
No new test, as this should cause no functional change.
Thanks,
Lars
> Optimize flushing of the Store cache for max versions and (new) min versions
> ----------------------------------------------------------------------------
>
> Key: HBASE-4241
> URL: https://issues.apache.org/jira/browse/HBASE-4241
> Project: HBase
> Issue Type: Improvement
> Components: regionserver
> Affects Versions: 0.92.0
> Reporter: Lars Hofhansl
> Assignee: Lars Hofhansl
> Attachments: 4241-v2.txt, 4241.txt
>
>
> As discussed with with Jon, there is room for improvement in how the memstore
> is flushed to disk.
> Currently only expired KVs are pruned before flushing, but we can also prune
> versions if we find at least maxVersions versions in the memstore.
> The same holds for the new minversion feature: If we find at least minVersion
> versions in the store we can remove all further versions that are expired.
> Generally we should use the same mechanism here that is used for Compaction.
> I.e. StoreScanner. We only need to add a scanner to Memstore that can scan
> along the current snapshot.
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