Message-ID: <01cc01c557ba$a4fdb0b0$f20214ac@bite.lt>
From: "Mindaugas Riauba" <mind@bi.lt>
To: <pgsql-performance@postgresql.org>
Subject: PostgreSQL strugling during high load
Date: Fri, 13 May 2005 15:52:38 +0300
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  Hello,

  We have problems with one postgresql database with high
data change rate. Actually we are already under pressure
to change postgresql to Oracle.

  I cannot post schema and queries to list but can do this
privately.

  Tables are not big (20000-150000 rows each) but have very high
turnover rate - 100+ updates/inserts/deletes/selects per second.
So contents of database changes very fast. Problem is that when
pg_autovacuum does vacuum those changes slows down too much.
And we keep autovacuum quite aggressive (-v 1000 -V 0.5 -a 1000
-A 0.1 -s 10) to not bloat database and to avoid bigger impact.
analyze seems not to impact performance too much.

  Tables have 2-3 indexes each and one table have foreign key
contraint. Postgresql is 8.0.1. vmstat shows that IO and CPU are
not saturated. DB is on RAID1+0 controller with battery backed write
cache.

  What can we tune to improve performance in our case? Please help
to defend PostgreSQL against Oracle in this case :).

  Thanks,

  Mindaugas