Re: SAVEPOINTs and COMMIT performance

From: Simon Riggs <simon(at)2ndQuadrant(dot)com>
To: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: SAVEPOINTs and COMMIT performance
Date: 2011-07-14 14:59:14
Message-ID: CA+U5nMJnrMWAzymxLoWkoH-oxpq7L4bsUO760buupHArLp7Tgw@mail.gmail.com
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On Mon, Jun 6, 2011 at 10:33 AM, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> On 06.02.2011 23:09, Simon Riggs wrote:
>>
>> On Sun, 2011-02-06 at 12:11 -0500, Bruce Momjian wrote:
>>>
>>> Did this ever get addressed?
>>
>> Patch attached.
>>
>> Seems like the easiest fix I can come up with.
>
>> @@ -2518,7 +2518,7 @@ CommitTransactionCommand(void)
>>                case TBLOCK_SUBEND:
>>                        do
>>                        {
>> -                               CommitSubTransaction();
>> +                               CommitSubTransaction(true);
>>                                s = CurrentTransactionState;    /* changed
>> by pop */
>>                        } while (s->blockState == TBLOCK_SUBEND);
>>                        /* If we had a COMMIT command, finish off the main
>> xact too */
>
> We also get into this codepath at RELEASE SAVEPOINT, in which case it is
> wrong to not reassign the locks to the parent subtransaction.

Attached patch splits TBLOCK_SUBEND state into two new states:
TBLOCK_SUBCOMMIT and TBLOCK_SUBRELEASE, so that we can do the right
thing.

--
 Simon Riggs                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

Attachment Content-Type Size
savepoint_commit_performance.v2.patch application/octet-stream 8.7 KB

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