AW: AW: vacuum

From: Zeugswetter Andreas SB <ZeugswetterA(at)wien(dot)spardat(dot)at>
To: "'The Hermit Hacker'" <scrappy(at)hub(dot)org>, Zeugswetter Andreas SB <ZeugswetterA(at)wien(dot)spardat(dot)at>
Cc: "'Mike Cianflone'" <mcianflone(at)littlefeet-inc(dot)com>, Hackers List <pgsql-hackers(at)postgresql(dot)org>
Subject: AW: AW: vacuum
Date: 2001-06-13 14:01:32
Message-ID: 11C1E6749A55D411A9670001FA687963368324@sdexcsrv1.f000.d0188.sd.spardat.at
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> The other question is, what are your startup parameters? What sort of
> shared memory buffer are you working with? I image that VACUUM does a
> flush to disk, so are 1000 items filling your buffer(s),
> causing an almost
> continue fsync to disk for each INSERT after that ... so the VACUUM is
> clearing the buffer(s) to disk, giving your space again to do quick
> INSERTs for 1000 records again?

Aah yes, you mean that the pages are only written during checkpoints ?
Then he would not need a vacuum, but a forced checkpoint.
That would actually impose, that we need yet another checkpoint initiating
event, e.g. do checkpoint when buffer is 75% dirty. Or better yet have
a daemon, that only writes out dirty pages from back to front of the LRU queue
until only a configurable amount of buffers is dirty.

Andreas

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