[jira] [Commented] (KUDU-2612) Implement multi-row transactions

["ASF subversion and git services (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KUDU-2612?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17276141#comment-17276141 ] 

ASF subversion and git services commented on KUDU-2612:
-------------------------------------------------------

Commit 8c5e655d2d29e7758f26a373ea240631722ea1cf in kudu's branch refs/heads/master from Andrew Wong
[ https://gitbox.apache.org/repos/asf?p=kudu.git;h=8c5e655 ]

KUDU-2612: loosen restrictions for BEGIN_COMMIT ops

This patch updates the state validations for the BEGIN_COMMIT. Rather
than only requiring an in-flight transaction to be kOpen (the common
case) or kCommitInProgress (if re-attempting a BEGIN_COMMIT call), it's
more robust to allow the call to be made even after the transaction has
already been finalized. This will allow a to-be-merged implementation of
a commit task to be retried with much less fuss.

Here's some pseudo-code for such a commit task:
1. persist COMMIT_IN_PROGRESS record on TxnStatusManager
2. foreach participant as p: BEGIN_COMMIT(p)
3. commit_ts = max timestamp used across BEGIN_COMMIT ops
4. foreach participant as p: FINALIZE_COMMIT(p, commit_ts)
5. persist COMMITTED record on TxnStatusManager

If the commit task is interrupted (e.g. by some crash)  between steps 3
and 5, we may be left with some participants with fully finalized
commits. In such cases, all other participants _must_ also finalize, and
they must finalize with the same timestamp. To ensure this, it must be
possible to re-run a commit task. However, re-running it without this
patch may lead to issues because the BEGIN_COMMIT ops would yield
errors, complaining about an illegal state on participants that were
finalized.

This patch allows for a BEGIN_COMMIT op to succeed and return
immediately if a FINALIZE_COMMIT op has already completed. If so, the
finalized commit timestamp is sent back, allowing for the above commit
task to be repeatable.

Change-Id: Ifa4c5314190c84648c1b1edea7aab776b4882f97
Reviewed-on: http://gerrit.cloudera.org:8080/16992
Tested-by: Kudu Jenkins
Reviewed-by: Alexey Serbin <as...@cloudera.com>


> Implement multi-row transactions
> --------------------------------
>
>                 Key: KUDU-2612
>                 URL: https://issues.apache.org/jira/browse/KUDU-2612
>             Project: Kudu
>          Issue Type: Task
>            Reporter: Mike Percy
>            Priority: Major
>              Labels: roadmap-candidate
>
> Tracking Jira to implement multi-row / multi-table transactions in Kudu.



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