pg.ddx.io  pgsql-hackers@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Jesper Krogh <jesper@krogh.cc>
To: Tomas Vondra <tv@fuzzy.cz>
Cc: pgsql-hackers@postgresql.org
Subject: Re: GIN improvements part2: fast scan
Date: Mon, 03 Feb 2014 14:59:29 +0100
Message-ID: <52EFA0C1.7060103@krogh.cc> (raw)
In-Reply-To: <52EEF472.9020106@fuzzy.cz>
References: <CAPpHfdvftaJq7www381naLw1=4u0h+qpXgWvNhcEB9HMVywbGg@mail.gmail.com>
	<51D00FB6.9030008@vmware.com>
	<CAPpHfdtsDe-O6oQdCZUh6N1gGOMz0XKTMNQro-fueg-R06PaWw@mail.gmail.com>
	<528533D9.3040501@vmware.com>
	<CAPpHfduOvUFT+GgCrnBOzRR19eTb9mDsDJwU=S0h477fdgr=RA@mail.gmail.com>
	<CAPpHfdtZOhsmz_uf5BfdXcj5W3zk3K-PYxFc8-7eQw-nPXX1DA@mail.gmail.com>
	<CAPpHfdsEKFmrOU51EWSbF-RDESasSVa2YjoyFoG+0jCZOn1qjw@mail.gmail.com>
	<CAPpHfdvs-EHiwmTgfK=uJ4W3OjskVHyfkuehtyrKfKY_KmMpVw@mail.gmail.com>
	<52E141BA.5000302@vmware.com>
	<52E4141E.60609@fuzzy.cz>
	<52E42AD0.5060600@vmware.com>
	<52E4AA3A.9000607@fuzzy.cz>
	<52E53458.2010106@vmware.com>
	<CAPpHfdticvY2+RGTxzQdrr4YSQie+vYGRDRBTuG1ZxBmjwGrOA@mail.gmail.com>
	<CAPpHfduivz3MOA8_o+44n_Z0P-n+WCW=K1DrH+-g3gb-cbM2aA@mail.gmail.com>
	<52E72A10.5040908@fuzzy.cz>
	<52E75C54.9050209@vmware.c om>
	<52E9A274.6040806@fuzzy.c z>
	<52EE21D1.2080804@vmware.com>
	<52EED0FC.2060503@fuzzy.cz>
	<52EEF472.9020106@fuzzy.cz>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-hackers>

On 03/02/14 02:44, Tomas Vondra wrote:
> (2) The question is whether the new patch works fine on rare words. See
>      this for comparison of the patches against HEAD:
>
>        http://www.fuzzy.cz/tmp/gin/3-rare-words.png
>        http://www.fuzzy.cz/tmp/gin/3-rare-words-new.png
>
>      and this is the comparison of the two patches:
>
>        http://www.fuzzy.cz/tmp/gin/patches-rare-words.png
>
>      That seems fine to me - some queries are slower, but we're talking
>      about queries taking 1 or 2 ms, so the measurement error is probably
>      the main cause of the differences.
>
> (3) With higher numbers of frequent words, the differences (vs. HEAD or
>      the previous patch) are not that dramatic as in (1) - the new patch
>      is consistently by ~20% faster.
Just thinking, this is about one algorithm is being better or frequent words
and another algorithm being better at rare words... we do have
this information (at least or tsvector) in the statistics, would
it be possible to just call the "consistent" function more often if the
statistics gives signs that it actually is a frequent word?

Jesper - heavily dependent on tsvector-searches, with both frequent and 
rare words.



-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers



view thread (90+ messages)  latest in thread

Message-ID: <52EFA0C1.7060103@krogh.cc>
Permalink:  ../52EFA0C1.7060103@krogh.cc/
Also on:    postgresql.org/message-id/52EFA0C1.7060103@krogh.cc

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-hackers@postgresql.org
  Cc: jesper@krogh.cc, tv@fuzzy.cz
  Subject: Re: GIN improvements part2: fast scan
  In-Reply-To: <52EFA0C1.7060103@krogh.cc>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox