[
https://issues.apache.org/jira/browse/HBASE-17887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16009979#comment-16009979
]
ramkrishna.s.vasudevan commented on HBASE-17887:
------------------------------------------------
Being the author of the HBASE-13082 patch I take the responsibility of
introducing this critical bug.
If you all feel this bug in 1.3 is going to be a pain, then I can take try to
revert the HBASE-13082 fix from 1.3. This was a very rare case of bug where two
consecutive flushes happen consecutively and some time when I ran
TestAcidGuarentees it was passing to me. But I should accept that when it
started failing frequently I did not pay attention to those failures as this
was fixed very long back. Thanks to [~chia7712] for fixing this critcal bug.
> Row-level consistency is broken for read
> ----------------------------------------
>
> Key: HBASE-17887
> URL: https://issues.apache.org/jira/browse/HBASE-17887
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 2.0.0, 1.3.0
> Reporter: Umesh Agashe
> Assignee: Chia-Ping Tsai
> Priority: Blocker
> Fix For: 2.0.0, 1.4.0, 1.3.2
>
> Attachments: HBASE-17887.branch-1.v0.patch,
> HBASE-17887.branch-1.v1.patch, HBASE-17887.branch-1.v1.patch,
> HBASE-17887.branch-1.v2.patch, HBASE-17887.branch-1.v2.patch,
> HBASE-17887.branch-1.v3.patch, HBASE-17887.branch-1.v4.patch,
> HBASE-17887.branch-1.v4.patch, HBASE-17887.branch-1.v4.patch,
> HBASE-17887.branch-1.v5.patch, HBASE-17887.branch-1.v6.patch,
> HBASE-17887.ut.patch, HBASE-17887.v0.patch, HBASE-17887.v1.patch,
> HBASE-17887.v2.patch, HBASE-17887.v3.patch, HBASE-17887.v4.patch,
> HBASE-17887.v5.patch, HBASE-17887.v5.patch
>
>
> The scanner of latest memstore may be lost if we make quick flushes. The
> following step may help explain this issue.
> # put data_A (seq id = 10, active store data_A and snapshots is empty)
> # snapshot of 1st flush (active is empty and snapshot stores data_A)
> # put data_B (seq id = 11, active store data_B and snapshot store data_A)
> # create user scanner (read point = 11, so It should see the data_B)
> # commit of 1st flush
> #* clear snapshot ((hfile_A has data_A, active store data_B, and snapshot is
> empty)
> #* update the reader (the user scanner receives the hfile_A)
> # snapshot of 2st flush (active is empty and snapshot store data_B)
> # commit of 2st flush
> #* clear snapshot (hfile_A has data_A, hfile_B has data_B, active is empty,
> and snapshot is empty) – this is critical piece.
> #* -update the reader- (haven't happen)
> # user scanner update the kv scanners (it creates scanner of hfile_A but
> nothing of memstore)
> # user see the older data A – wrong result
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
