Re: Postgresql 'eats' all mi data partition

Quoting Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com>:

> On Thu, 25 Sep 2003, Javier Carlos wrote:
>
> >
> ============================================================================
> > POSTGRESQL BUG REPORT TEMPLATE
> >
> ============================================================================
> >
> >
> > Your name : Javier Carlos Rivera
> > Your email address : fjcarlos ( at ) correo ( dot ) insp ( dot ) mx
> >
> >
> > System Configuration
> > ----------------------
> > Architecture (example: Intel Pentium) : Intel Pentium 4
> >
> > Operating System (example: Linux 2.0.26 ELF) : Debian GNU/Linux
3.0
> 2.4.21
> >
> > RAM : 256 MB
> >
> > PostgreSQL version (example: PostgreSQL-6.3.2) : PostgreSQL-7.3.4
> >
> > Compiler used (example: gcc 2.7.2) : 2.95.4
> >
> >
> >
> > Please enter a FULL description of your problem:
> > -------------------------------------------------
> > On Thursday Bruce Momjian was at Mexico; I saw him and asked about
> > this problem. He told me to write to this e-mail.
> >
> > When I do a simple 'UPDATE' PostgreSQL 'eats' all my partition space
> > of my data directory. For example:
> >
> > ***** My data directory is in /var
> > ***** BEFORE I do the UPDATEs I got this from df:
> > OPORTUNIDADES:~# df
> > Filesystem 1k-blocks Used Available Use% Mounted on
> > /dev/hda2 2885812 14372 2724848 1% /
> > /dev/hda1 14421344 1195132 12493652 9% /var
> > /dev/hda3 7692908 888560 6413568 13% /usr
> > /dev/hda6 12491804 22704 11834536 1% /javier
> > /dev/hda7 1494204 23936 1394364 2% /home
> >
> >
> > ***** Then I do the UPDATEs:
> > **** The updates are of this type :
> > UPDATE tbl_personas SET "PIDFOLIO"=-2 WHERE "PIDFOLIO" IS NULL;
> > UPDATE tbl_personas SET "P5_1"=-2 WHERE "P5_1" IS NULL;
> > UPDATE tbl_personas SET "P4PAQ"=-2 WHERE "P4PAQ" IS NULL;
> > UPDATE tbl_personas SET "P5_4"=-2 WHERE "P5_4" IS NULL;
> > UPDATE tbl_personas SET "P5_5"=-2 WHERE "P5_5" IS NULL;
> > UPDATE tbl_personas SET "P36_4"=-2 WHERE "P36_4" IS NULL;
> > ..
> > UPDATE table_name SET column_name = -2 WHERE column_name IS NULL;
> > ..
>
> If you're not vacuuming, you're going to have a potentially large
> number of dead rows. Does a vacuum between updates or a vacuum full at
> the end bring the space usage down to something reasonable?
>

I did a vacuumbdb after the updates, and the space usage didn't down to
something reasonable. For example, I had a 250MB database, then I did about
300 query updates, and mi partition growed up until fill all mi data partition
space of 15GB. After that I did an vacuumdb and only the space down 100MB.
After that I DROPPED the database, and the space down ALL the 15GB; It's very
weird, don't you think?

Cheers,

Javier

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