Horton

Re: [COMMITTERS] pgsql: Make group commit more effective.

Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>

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From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-hackers@postgresql.org
Date: 2012-01-30T22:20:15Z
Lists: pgsql-hackers

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  1. Make group commit more effective.

On 30.01.2012 23:06, Heikki Linnakangas wrote:
> On 30.01.2012 22:50, Heikki Linnakangas wrote:
>> On 30.01.2012 20:27, Robert Haas wrote:
>>> Either this patch, or something else committed this morning, is
>>> causing "make check" to hang or run extremely slowly for me. I think
>>> it's this patch, because I attached to a backend and stopped it a few
>>> times, and all the backtraces look like this:
>>
>> Yeah, sure looks like it's the group commit commit. It works for me, and
>> staring at the code, I have no idea what could be causing it. The
>> buildfarm seems happy too, so this is pretty mysterious.
>
> And just after sending that, I succeeded to reproduce this. I had to
> lower wal_buffers to a small value to make it happen. I'm debugging this
> now..

It was a bug in the LWLockRelease code, after all. Fixed. Unfortunately 
this added a couple more instructions to that critical codepath, but I 
think it should still go without notice. Let me know if this doesn't fix 
the hang on your laptop.

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com