Bad rules

Steve King <steve.king@ecmsys.co.uk> writes:

I am using postgres 7.2, and have rule on a table which causes a notify if
an insert/update/delete is performed on the table.
The table is very very small.
When performing a simple (very simple) update on the table this takes about
3 secs, when I remove the rule it is virtually instantaneous.
The rest of the database seems to perform fine, have you any ideas or come
across this before??

Let's see the rule exactly? NOTIFY per se is not slow in my experience.

(One thing to ask: have you done a VACUUM FULL on pg_listener in recent
memory? Heavy use of LISTEN/NOTIFY does tend to bloat that table if you
don't keep after it with VACUUM.)

regards, tom lane

Thankyou very much for your enlightened comment, it worked a treat.

I do not seem to be able to find references to this kind of useful
information in the postgresql online manual or in books such as bruce
momjian's 'postgresql-introduction and concepts'. Where is this info to be
found other than the mailing list?

Thanks again.
Regards
Steve

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
Sent: 04 October 2002 15:48
To: Steve King
Cc: PostgreSQL-development
Subject: Re: [HACKERS] Bad rules

Steve King <steve.king@ecmsys.co.uk> writes:

I am using postgres 7.2, and have rule on a table which causes a notify if
an insert/update/delete is performed on the table.
The table is very very small.
When performing a simple (very simple) update on the table this takes

about

3 secs, when I remove the rule it is virtually instantaneous.
The rest of the database seems to perform fine, have you any ideas or come
across this before??

Let's see the rule exactly? NOTIFY per se is not slow in my experience.

(One thing to ask: have you done a VACUUM FULL on pg_listener in recent
memory? Heavy use of LISTEN/NOTIFY does tend to bloat that table if you
don't keep after it with VACUUM.)

regards, tom lane