PG 8.1.2 CYGWIN 1.5.17 VACUUM very slow.

Hello,

i have installed a self compiled PostgreSQL 8.1.2 with cygwin 1.5.17
on a computer with Windows 2000 Professional SP4, Celeron 1.7 GHz and
768 MB.

There I have database that contains two tables with about 7 million
rows, one 3 million the other 4 million. I deleted from the on 1.5
million rows and the other 3 million rows.

Then i started a full vacuum with

vaccuumdb -v -f -z -p 5433 mydb

and the vaccuum is still running after more than 3 hours. The
vacuum_cost_delay is 50 milliseconds, to avoid that the vacuum-process
blocks all further processes on the computer. The vacuum work memory
is 16 MB.

With PostgreSQL 7.4.x vacuum would finish after about half an hour.

Is that normal? The slow vacuum with PostgreSQL 8.1.2 seems to be a
bug for me.

I also noticed on a normal vacuum with analyze, without any row
deletions before, that the vacuum of PostgreSQL 7.4.x was about five
times faster than 8.1, with no vacuum_cost_delay for 8.1. I thought
the vacuum of PostgreSQL 8.x should better perform than the one of
7.4.x. But with the state it is now, PostgreSQL 8.1.x is on cygwin only
useable for little databases with a few thousand rows.

Regards,
Roland.

--
Roland Walter mailto: rwa (at) mosaic-ag (dot) com
MOSAIC SOFTWARE AG phone: +49 (0) 22 25 / 88 2-41 1
Am Pannacker 3 fax: +49 (0) 22 25 / 88 2-20 1
D-53340 Meckenheim http://www.mosaic-ag.com

Die in dieser E-Mail enthaltenen Nachrichten und Anhaenge sind ausschliesslich
fuer den bezeichneten Adressaten bestimmt. Sie koennen rechtlich geschuetzte,
vertrauliche Informationen enthalten. Falls Sie nicht der bezeichnete Empfaenger
oder zum Empfang dieser E-Mail nicht berechtigt sind, ist die Verwendung,
Vervielfaeltigung oder Weitergabe von Nachrichten und Anhaengen untersagt.
Falls Sie diese E-Mail irrtuemlich erhalten haben, informieren Sie bitte
unverzueglich den Absender und vernichten Sie die E-Mail.

This e-mail message and any attachment are intended exclusively for the named
addressee. They may contain confidential information which may also be protected
by professional secrecy. Unless you are the named addressee (or authorised to
receive for the addressee) you may not copy or use this message or any attachment
or disclose the contents to anyone else. If this e-mail was sent to you by mistake
please notify the sender immediately and delete this e-mail.