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From "Liu Shaohui (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HBASE-10118) Major compact keeps deletes with future timestamps
Date Wed, 26 Mar 2014 03:57:21 GMT

     [ https://issues.apache.org/jira/browse/HBASE-10118?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Liu Shaohui updated HBASE-10118:
--------------------------------

    Attachment: HBASE-10118-trunk-v2.diff

Thanks for [~yuzhihong@gmail.com]'s careful review.

> Major compact keeps deletes with future timestamps
> --------------------------------------------------
>
>                 Key: HBASE-10118
>                 URL: https://issues.apache.org/jira/browse/HBASE-10118
>             Project: HBase
>          Issue Type: Bug
>          Components: Compaction, Deletes, regionserver
>            Reporter: Max Lapan
>            Assignee: Liu Shaohui
>            Priority: Minor
>             Fix For: 0.99.0
>
>         Attachments: HBASE-10118-trunk-v1.diff, HBASE-10118-trunk-v2.diff
>
>
> Hello!
> During migration from HBase 0.90.6 to 0.94.6 we found changed behaviour in how major
compact handles delete markers with timestamps in the future. Before HBASE-4721 major compact
purged deletes regardless of their timestamp. Newer versions keep them in HFile until timestamp
not reached.
> I guess this happened due to new check in ScanQueryMatcher {{EnvironmentEdgeManager.currentTimeMillis()
- timestamp) <= timeToPurgeDeletes}}.
> This can be worked around by specifying large negative value in {{hbase.hstore.time.to.purge.deletes}}
option, but, unfortunately, negative values are pulled up to zero by Math.max in HStore.java.
> Maybe, we are trying to do something weird by specifing delete timestamp in future, but
HBASE-4721 definitely breaks old behaviour we rely on.
> Steps to reproduce this:
> {code}
> put 'test', 'delmeRow', 'delme:something', 'hello'
> flush 'test'
> delete 'test', 'delmeRow', 'delme:something', 1394161431061
> flush 'test'
> major_compact 'test'
> {code}
> Before major_compact we have two hfiles with the following:
> {code}
> first:
> K: delmeRow/delme:something/1384161431061/Put/vlen=5/ts=0
> second:
> K: delmeRow/delme:something/1394161431061/DeleteColumn/vlen=0/ts=0
> {code}
> After major compact we get the following:
> {code}
> K: delmeRow/delme:something/1394161431061/DeleteColumn/vlen=0/ts=0
> {code}
> In our installation, we resolved this by removing Math.max and setting hbase.hstore.time.to.purge.deletes
to Integer.MIN_VALUE, which purges delete markers, and it looks like a solution. But, maybe,
there are better approach.



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