Horton

Re: [HACKERS] Small improvement to compactify_tuples

Andres Freund <andres@anarazel.de>

View thread View on postgr.es
From: Andres Freund <andres@anarazel.de>
To: Yura Sokolov <funny.falcon@gmail.com>
Cc: Stephen Frost <sfrost@snowman.net>, Michael Paquier <michael.paquier@gmail.com>, Peter Geoghegan <pg@bowt.ie>, Tom Lane <tgl@sss.pgh.pa.us>, Claudio Freire <klaussfreire@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Sokolov Yura <funny.falcon@postgrespro.ru>, Alvaro Herrera <alvherre@2ndquadrant.com>, Heikki Linnakangas <hlinnaka@iki.fi>, PostgreSQL-Dev <pgsql-hackers@postgresql.org>
Date: 2018-03-01T19:22:06Z
Lists: pgsql-hackers 
Hi,

On 2018-02-25 21:39:46 +0300, Yura Sokolov wrote:
> > If that's the case then does it really make sense to make this change..?
> 
> I don't think it is really necessary to implement generic version
> through templated.

Why?

> Updated numbers are (same benchmark on same notebook, but with new
> master, new ubuntu and later patch version) (average among 6 runs):
> 
> master               - 16135tps
> with templated qsort - 16199tps
> with bucket sort     - 16956tps
> 
> Difference is still measurable, but less significant. I don't know why.
> 
> Rebased version of first patch (qsorted tamplate) is in atttach.

Hm, that's a bit underwhelming. It's nice to deduplicate, but 16135tps
-> 16199tps is barely statistically significant?

- Andres

Commits

  1. Avoid looping through line pointers twice in PageRepairFragmentation().

  2. Reduce pinning and buffer content locking for btree scans.

  3. Speed up in-memory tuplesorting.