[jira] [Commented] (HBASE-6195) Increment data will be lost when the memstore is flushed

["Hadoop QA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-6195?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13293268#comment-13293268 ] 

Hadoop QA commented on HBASE-6195:
----------------------------------

-1 overall.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12531685/HBASE-6195-trunk-V3.patch
  against trunk revision .

    +1 @author.  The patch does not contain any @author tags.

    -1 tests included.  The patch doesn't appear to include any new or modified tests.
                        Please justify why no new tests are needed for this patch.
                        Also please list what manual steps were performed to verify this patch.

    +1 hadoop2.0.  The patch compiles against the hadoop 2.0 profile.

    +1 javadoc.  The javadoc tool did not generate any warning messages.

    +1 javac.  The applied patch does not increase the total number of javac compiler warnings.

    -1 findbugs.  The patch appears to introduce 5 new Findbugs (version 1.3.9) warnings.

    +1 release audit.  The applied patch does not increase the total number of release audit warnings.

    +1 core tests.  The patch passed unit tests in .

Test results: https://builds.apache.org/job/PreCommit-HBASE-Build/2138//testReport/
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/2138//artifact/trunk/patchprocess/newPatchFindbugsWarningshbase-common.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/2138//artifact/trunk/patchprocess/newPatchFindbugsWarningshbase-server.html
Console output: https://builds.apache.org/job/PreCommit-HBASE-Build/2138//console

This message is automatically generated.
                
> Increment data will be lost when the memstore is flushed
> --------------------------------------------------------
>
>                 Key: HBASE-6195
>                 URL: https://issues.apache.org/jira/browse/HBASE-6195
>             Project: HBase
>          Issue Type: Bug
>          Components: regionserver
>            Reporter: Xing Shi
>            Assignee: ShiXing
>         Attachments: HBASE-6195-trunk-V2.patch, HBASE-6195-trunk-V3.patch, HBASE-6195-trunk.patch
>
>
> There are two problems in increment() now:
> First:
> I see that the timestamp(the variable now) in HRegion's Increment() is generated before got the rowLock, so when there are multi-thread increment the same row, although it generate earlier, it may got the lock later. Because increment just store one version, so till now, the result will still be right.
> When the region is flushing, these increment will read the kv from snapshot and memstore with whose timestamp is larger, and write it back to memstore. If the snapshot's timestamp larger than the memstore, the increment will got the old data and then do the increment, it's wrong.
> Secondly:
> Also there is a risk in increment. Because it writes the memstore first and then HLog, so if it writes HLog failed, the client will also read the incremented value.

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