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


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