Hello Alexey Serbin, Kudu Jenkins, Todd Lipcon,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/8859
to look at the new patch set (#2).
Change subject: KUDU-2115: remove unnecessary compaction selection check
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KUDU-2115: remove unnecessary compaction selection check
Tablets will perform compaction selection on a copy of the currently
available rowsets in order to avoid holding the component_lock_ for the
duration of rowset selection.
It is then verified that nothing else compacted the selected rowsets by
iterating over the selected rowsets and checking that they still exist
to be compacted.
However, the initial selection of rowsets is performed on a snapshotted
copy of the available rowsets, and in between the snapshot of the
rowsets and the verification, the component_lock_ is dropped. As such,
the verification hits false negatives if other threads are able to take
the component_lock_ and modify the available rowsets.
The verification itself is unnecessary, as the correct set of rowsets
would be returned by PickRowSetsToCompact(), even if the verification
were to fail, so I've removed it.
I verified the diagnosis by placing a random sleep just after making the
copy in PickRowSetsToCompact() and seeing
TabletServerDiskFailureTest.TestRandomOpSequence, which schedules many
compactions, fail consistently with the failed verification. Upon making
the fix, this passes.
Change-Id: I4dab330d61facb18717f6faf179f9b94a9e55236
---
M src/kudu/tablet/tablet.cc
1 file changed, 0 insertions(+), 18 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/59/8859/2
--
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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I4dab330d61facb18717f6faf179f9b94a9e55236
Gerrit-Change-Number: 8859
Gerrit-PatchSet: 2
Gerrit-Owner: Andrew Wong <aw...@cloudera.com>
Gerrit-Reviewer: Alexey Serbin <aser...@cloudera.com>
Gerrit-Reviewer: Andrew Wong <aw...@cloudera.com>
Gerrit-Reviewer: Kudu Jenkins
Gerrit-Reviewer: Todd Lipcon <t...@apache.org>
