Re: [HACKERS] Optimizer fed bad data about some system-table indexes

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Optimizer fed bad data about some system-table indexes
Date: 1999-05-01 19:06:48
Message-ID: 11096.925585608@sss.pgh.pa.us
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Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us> writes:
> Hmm. If you can get it to work without the file, great, or you could
> just delete the file when vacuum is performed, so the next backend
> recreates the file. That would work too.

That's a good idea. I made a test database with a couple thousand
tables in it, and found that when pg_class gets that big it does take
a measurable amount of time to rebuild the index info if the relcache
init file is not there. (Looked like about a third of a second on my
machine.) Since backend startup time is a hotbutton item for some
folks, I'm not going to take out the init file code. I'll just make
VACUUM remove the file, and then the first backend start after a VACUUM
will rebuild the file with up-to-date statistics for the system indexes.

regards, tom lane

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