Re: Vacuum now uses AccessShareLock for analyze - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Vacuum now uses AccessShareLock for analyze
Date
Msg-id 200005291613.MAA12883@candle.pha.pa.us
Whole thread Raw
In response to Re: Vacuum now uses AccessShareLock for analyze  (The Hermit Hacker <scrappy@hub.org>)
Responses Re: Vacuum now uses AccessShareLock for analyze  (The Hermit Hacker <scrappy@hub.org>)
List pgsql-hackers
> 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@candle.pha.pa.us               |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026
 


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