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https://issues.apache.org/jira/browse/CASSANDRA-4905?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13663449#comment-13663449
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Michael Theroux commented on CASSANDRA-4905:
--------------------------------------------
Can anyone comment on the risk of a user (such as myself) backporting this fix
and patching locally? The code that was changed in the patch looks identical
in 1.1.11.
We have a situation where a column family with lots of deletes running under
leveled compaction. The validation doesn't take too long, but afterwards we
get 2k compaction tasks that takes several hours to run, when really there
shouldn't be any inconsistency. What I suspect is happening is as tombstones
are getting gc_graced they are compacted away on some nodes and not others at
the time repair is run. I suspect the majority of the 2k compactions are
gc_graced tombstones getting back in-sync.
I'm setting up a test environment with baseline data, going to reproduce the
repair, reset to baseline, and re-run the repair with this patch to see if this
is indeed the issue. This might take a few days to setup and run.
Cassandra is mission and business critical for us. Moving to 1.2 will take
some time, as we should setup a test environment, practice migrations and test.
We also use the ByteOrderedPartitioner, which in general concerns me as its
not the most popular use of Cassandra, and maybe a source of issues as its
pounded on less by the general user community.
> Repair should exclude gcable tombstones from merkle-tree computation
> --------------------------------------------------------------------
>
> Key: CASSANDRA-4905
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4905
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Christian Spriegel
> Assignee: Sylvain Lebresne
> Fix For: 1.2.0 beta 3
>
> Attachments: 4905.txt
>
>
> Currently gcable tombstones get repaired if some replicas compacted already,
> but some are not compacted.
> This could be avoided by ignoring all gcable tombstones during merkle tree
> calculation.
> This was discussed with Sylvain on the mailing list:
> http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/repair-compaction-and-tombstone-rows-td7583481.html
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