Обсуждение: Bad rules

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Bad rules

От
Steve King
Дата:
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??

Regards
Steve



Re: Bad rules

От
Tom Lane
Дата:
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


Re: Bad rules

От
Steve King
Дата:
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