From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | t-ishii(at)sra(dot)co(dot)jp |
Cc: | Mike Mascari <mascarim(at)yahoo(dot)com>, Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp>, pgsql-hackers(at)postgreSQL(dot)org |
Subject: | Re: [HACKERS] vacuum process size |
Date: | 1999-08-24 15:05:28 |
Message-ID: | 2107.935507128@sss.pgh.pa.us |
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Lists: | pgsql-hackers |
Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp> writes:
> I have tested your idea and found even more improved memory usage
> (86MB vs. 43MB). Standard vacuum consumes as much as 478MB memory with
> deleting 5000000 tuples that would not be acceptable for most
> configurations. I think we should fix this as soon as possible. If
> there's no objection, I will commit included patches to the stable
> tree (seems Tom has more aggressive idea, so I'll leave the current
> tree as it is).
No, please make the change in current as well. I was thinking about
tweaking aset.c to be smarter about releasing large chunks, but in any
case having the doubling behavior at the request point will be a big
improvement.
I do not like your patch as given, however. By using a static variable
you are assuming that there is only one active VPageList at a time.
It looks to me like there are at least two --- and there is no reason
to think they'd be the same size.
You need to add a num_pages field to the VPageList struct, not use
a static.
regards, tom lane
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