Skip site navigation (1) Skip section navigation (2)

Re: TODO-Item: B-tree fillfactor control

From: Simon Riggs <simon(at)2ndquadrant(dot)com>
To: ITAGAKI Takahiro <itagaki(dot)takahiro(at)lab(dot)ntt(dot)co(dot)jp>
Cc: pgsql-patches(at)postgresql(dot)org
Subject: Re: TODO-Item: B-tree fillfactor control
Date: 2006-02-13 12:59:30
Message-ID: 1139835570.1258.761.camel@localhost.localdomain (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-patches
On Fri, 2006-02-10 at 19:12 +0900, ITAGAKI Takahiro wrote:
> Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> > I'm surprised that you do not use the parameter to control the RIGHTMOST
> > index block split factor for B-trees, which remains at a constant 67%.
> > The PCTFREE only seems to apply at CREATE INDEX time.
> 
> Thanks for pointing out. I did not inadvertently use fillfactor on
> the rightmost page. With the revised patch, PCTFREE will be considered
> in such cases.
> 
> # CREATE TABLE test (i int);
> # INSERT INTO test SELECT generate_series(1, 100000);
> # CREATE INDEX btree ON test USING btree (i) PCTFREE 0;
> # SELECT relpages from pg_class where relname ='btree';
> relpages | 249
> # INSERT INTO test SELECT generate_series(100001, 200000);
> # SELECT relpages from pg_class where relname ='btree';
> relpages | 497    <-- +99.6%
> 

This additional functionality looks like it would work for b-trees. I've
not looked at this for GIST and hash indexes.

The reduction in index size should give useful performance gains on
larger, growing tables with increasing keys. We'll test that.

Best Regards, Simon Riggs




In response to

pgsql-hackers by date

Next:From: Magnus Naeslund(f)Date: 2006-02-13 14:04:38
Subject: Postgresql crash (signal 11). keywords: distinct, subselect, union
Previous:From: Mark WoodwardDate: 2006-02-13 12:57:24
Subject: Re: Why don't we allow DNS names in pg_hba.conf?

pgsql-patches by date

Next:From: Tom LaneDate: 2006-02-13 14:57:41
Subject: Re: patch correcting the build failure on machines without readline
Previous:From: Sergey E. KoposovDate: 2006-02-13 12:31:09
Subject: patch correcting the build failure on machines without readline

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group