Re: Patch to improve performance of replay of AccessExclusiveLock

On 16 March 2017 at 19:08, Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Thu, Mar 16, 2017 at 6:01 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>> On 8 March 2017 at 10:02, David Rowley <david.rowley@2ndquadrant.com> wrote:
>>> On 8 March 2017 at 01:13, Simon Riggs <simon@2ndquadrant.com> wrote:
>>>> Don't understand this. I'm talking about setting a flag on
>>>> commit/abort WAL records, like the attached.
>>>
>>> There's nothing setting a flag in the attached. I only see the
>>> checking of the flag.
>>
>> Yeh, it wasn't a full patch, just a way marker to the summit for you.
>>
>>>> We just need to track info so we can set the flag at EOXact and we're done.
>>>
>>> Do you have an idea where to store that information? I'd assume we'd
>>> want to store something during LogAccessExclusiveLocks() and check
>>> that in XactLogCommitRecord() and XactLogAbortRecord(). I don't see
>>> anything existing which might help with that today. Do you think I
>>> should introduce some new global variable for that? Or do you propose
>>> calling GetRunningTransactionLocks() again while generating the
>>> Commit/Abort record?
>>
>> Seemed easier to write it than explain further. Please see what you think.
>>
>
> @@ -5563,7 +5575,8 @@ xact_redo_abort(xl_xact_parsed_abort *parsed,
> TransactionId xid)
>   /*
>   * Release locks, if any. There are no invalidations to send.
>   */
> - StandbyReleaseLockTree(xid, parsed->nsubxacts, parsed->subxacts);
> + if (parsed->xinfo & XACT_XINFO_HAS_AE_LOCKS)
> + StandbyReleaseLockTree(xid, parsed->nsubxacts, parsed->subxacts);
>
>
> The patch uses XACT_XINFO_HAS_AE_LOCKS during abort replay, but during
> normal operation (XactLogAbortRecord()), it doesn't seem to log the
> information.  Is this an oversight or do you have some reason for
> doing so?

Good catch, thanks. Yes, I changed my mind on whether it was needed
during implementation.

-- 
Simon Riggs                http://www.2ndQuadrant.com/
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