Re: 7.0.2 -> 7.1 performance drop

From: Alvaro Herrera <alvherre(at)atentus(dot)com>
To: Frank Bax <fbax(at)sympatico(dot)ca>
Cc: "Brent R(dot) Matzelle" <bmatzelle(at)yahoo(dot)com>, <pgsql-general(at)postgresql(dot)org>
Subject: Re: 7.0.2 -> 7.1 performance drop
Date: 2001-11-12 23:19:08
Message-ID: Pine.LNX.4.33L2.0111122016100.31929-100000@aguila.protecne.cl
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On Mon, 12 Nov 2001, Frank Bax wrote:

> Expecting more questions like yours, I did a little more research. The
> import is all INSERT's except for two selects. I realised I could rewrite
> a portion of the code to remove one of those SELECT's. Guess What no
> effect on run-time. Isn't that curious? So I pondered that for a while
> and thought that if removeing one SELECT didn't make any difference, then
> making changes to the second SELECT (which was on same table) wsn't likely
> to change anything either. If that's true then the problem was only
> INSERT's. A little more pondering and I remember that I looked a little
> closer at startup parms during the PG upgrade. I had removed -F option.
> Put it back in and runtime dropped to 10 minutes again - problem solved!

Maybe you are paying too much transaction overhead. Is your script one
single transaction? If you explicitly make it so by means of enclosing
it all in a BEGIN-COMMIT block (or several, depending on how much INSERT
clauses you have) it will perhaps run much faster.

HTH...

--
Alvaro Herrera (<alvherre[(at)]atentus(dot)com>)
"Crear es tan dificil como ser libre" (Elsa Triolet)

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