Re: Vacuum now uses AccessShareLock for analyze

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: The Hermit Hacker <scrappy(at)hub(dot)org>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Vacuum now uses AccessShareLock for analyze
Date: 2000-05-29 16:13:51
Message-ID: 200005291613.MAA12883@candle.pha.pa.us
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> On Mon, 29 May 2000, Bruce Momjian wrote:
>
> > I have changed vacuum so analyze now uses AccessShareLock. (Is this the
> > proper lock for analyze?)
> >
> > The code will now vacuum all requested relations. It will then analyze
> > each relation. This way, all the exclusive vacuum work is done first,
> > then analyze can continue with shared locks.
>
> hrmmm, here's a thought ... why not vacuum->analyze each relation in
> order? the 'exclusive lock' will prevent anyone from reading, so do a
> relation, release the lock to analyze that relation and let ppl access the
> database ... then do the next ... instead of doing an exclusive lock for
> the duration of the whole database ...

No, each table is locked one at a time. We do all the single-table
locks first so the rest is all shared access. Does that make sense?

--
Bruce Momjian | http://www.op.net/~candle
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
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