Horton

Re: StandbyRecoverPreparedTransactions recovers subtrans links incorrectly

Michael Paquier <michael.paquier@gmail.com>

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From: Michael Paquier <michael.paquier@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Simon Riggs <simon@2ndquadrant.com>, Nikhil Sontakke <nikhils@2ndquadrant.com>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-04-27T02:10:34Z
Lists: pgsql-hackers 
On Thu, Apr 27, 2017 at 2:25 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Simon Riggs <simon@2ndquadrant.com> writes:
>> I've added code following Michael and Tom's comments to the previous
>> patch. New patch attached.
>
> Couple of minor suggestions:
>
> * Rather than deleting the comment for SubTransSetParent entirely,
> maybe make it say "It's possible that the parent was already recorded.
> However, we should never be asked to change an already-set entry to
> something else."
>
> * In SubTransGetTopmostTransaction, maybe it'd be better to spell
> "TransactionIdFollowsOrEquals" as "!TransactionIdPrecedes" to make
> it look more like the test just above.  Matter of taste though.
>
> * Less a matter of taste is that I think that should be just elog(ERROR);
> there's no good reason to make it FATAL.
>
> * Also, I think there should be a comment there, along the lines of
> "check for reversed linkage to ensure this isn't an infinite loop".

No more comments from here, thanks for working on the patch.
-- 
Michael

Commits

  1. Rework handling of subtransactions in 2PC recovery

  2. Fix order of arguments to SubTransSetParent().

  3. Speedup 2PC recovery by skipping two phase state files in normal path