Re: [SQL] OFFSET impact on Performance???

From: Alex Turner <armtuk(at)gmail(dot)com>
To: Richard Huxton <dev(at)archonet(dot)com>
Cc: Andrei Bintintan <klodoma(at)ar-sd(dot)net>, pgsql-sql(at)postgresql(dot)org, pgsql-performance(at)postgresql(dot)org
Subject: Re: [SQL] OFFSET impact on Performance???
Date: 2005-01-20 16:39:16
Message-ID: 33c6269f05012008391490448b@mail.gmail.com
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I am also very interesting in this very question.. Is there any way to
declare a persistant cursor that remains open between pg sessions?
This would be better than a temp table because you would not have to
do the initial select and insert into a fresh table and incur those IO
costs, which are often very heavy, and the reason why one would want
to use a cursor.

Alex Turner
NetEconomist

On Thu, 20 Jan 2005 15:20:59 +0000, Richard Huxton <dev(at)archonet(dot)com> wrote:
> Andrei Bintintan wrote:
> >> If you're using this to provide "pages" of results, could you use a
> >> cursor?
> >
> > What do you mean by that? Cursor?
> >
> > Yes I'm using this to provide "pages", but If I jump to the last pages
> > it goes very slow.
>
> DECLARE mycursor CURSOR FOR SELECT * FROM ...
> FETCH FORWARD 10 IN mycursor;
> CLOSE mycursor;
>
> Repeated FETCHes would let you step through your results. That won't
> work if you have a web-app making repeated connections.
>
> If you've got a web-application then you'll probably want to insert the
> results into a cache table for later use.
>
> --
> Richard Huxton
> Archonet Ltd
>
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