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https://issues.apache.org/jira/browse/HBASE-4487?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13117677#comment-13117677
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jirapos...@reviews.apache.org commented on HBASE-4487:
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Looks good. I like the bench marking tool.
This is like a group commit in HLog. We have a group committing going on
inside in sync down in dfsclient. Does this group commit not 'group' enough.
With this change, its no longer possible to sync each increment. We ok w/
that? We should at least release note this difference in increment behaviors
and erring on the conservative side, I'd mark this an 'incompatible change'
rather than an 'improvement' just so its more likely folks will know of this
changed increment behavior.
- Michael
On 2011-09-29 19:27:36, Dhruba Borthakur wrote:
bq.
bq. -----------------------------------------------------------
bq. This is an automatically generated e-mail. To reply, visit:
bq. https://reviews.apache.org/r/2116/
bq. -----------------------------------------------------------
bq.
bq. (Updated 2011-09-29 19:27:36)
bq.
bq.
bq. Review request for hbase and Ted Yu.
bq.
bq.
bq. Summary
bq. -------
bq.
bq. The increment operation releases the rowlock before doing the sync to the
HLog. This improves performance of increments on hot rows. Introduced method
HLog.appendNoSync() that returns a txid. The increment method then release the
rowlock and invokes HLog.sync(txid). The HLog.sync(txid) returns only if all
the transactions upto the one identified by that txid has been successfully
sycned to HDFS.
bq.
bq. There is a single test TestIncrement that creates a 100 threads and
ensures that all the concurrent increments match the final expected result.
There is a benchmark TestHLogBench that measures the performance of the
appendNoSync call.
bq.
bq.
bq. This addresses bug HBASE-4487.
bq. https://issues.apache.org/jira/browse/HBASE-4487
bq.
bq.
bq. Diffs
bq. -----
bq.
bq. /src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java 1177401
bq. /src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLog.java
1177401
bq. /src/test/java/org/apache/hadoop/hbase/regionserver/TestIncrement.java
PRE-CREATION
bq.
/src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestHLogBench.java
PRE-CREATION
bq.
/src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestWALActionsListener.java
1177401
bq.
/src/test/java/org/apache/hadoop/hbase/replication/regionserver/TestReplicationSourceManager.java
1177401
bq.
bq. Diff: https://reviews.apache.org/r/2116/diff
bq.
bq.
bq. Testing
bq. -------
bq.
bq. All unit tests pass now (expect TestDistributedLogSplitting,
TestRollingRestart, TestHTablePool), but I am seeing the same test to fail on
trunk, so these failures do not seem to be related to this patch.
bq.
bq.
bq. Thanks,
bq.
bq. Dhruba
bq.
bq.
> The increment operation can release the rowlock before sync-ing the Hlog
> ------------------------------------------------------------------------
>
> Key: HBASE-4487
> URL: https://issues.apache.org/jira/browse/HBASE-4487
> Project: HBase
> Issue Type: Improvement
> Reporter: dhruba borthakur
> Assignee: dhruba borthakur
> Attachments: appendNoSync4.txt, appendNoSync5.txt, appendNoSync6.txt
>
>
> This allows for better throughput when there are hot rows.I have seen this
> change make a single row update improve from 400 increments/sec/server to
> 4000 increments/sec/server.
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