Horton

Re: Speed up transaction completion faster after many relations are accessed in a transaction

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, "Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>, "Imai, Yoshikazu" <imai.yoshikazu@jp.fujitsu.com>, Simon Riggs <simon@2ndquadrant.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2019-04-07T15:47:19Z
Lists: pgsql-hackers 
Hi,

On 2019-04-08 03:40:52 +1200, David Rowley wrote:
> On Mon, 8 Apr 2019 at 03:20, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >
> > David Rowley <david.rowley@2ndquadrant.com> writes:
> > > The reason I thought it was a good idea to track some history there
> > > was to stop the lock table constantly being shrunk back to the default
> > > size every time a simple single table query was executed.
> >
> > I think that's probably gilding the lily, considering that this whole
> > issue is pretty new.  There's no evidence that expanding the local
> > lock table is a significant drag on queries that need a lot of locks.
> 
> Okay.  Here's another version with all the average locks code removed
> that only recreates the table when it's completely empty.

Could you benchmark your adversarial case?

- Andres

Commits

  1. Reorder LOCALLOCK structure members to compact the size

  2. Be more careful to not lose sync in the FE/BE protocol.