From: | Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-committers(at)postgresql(dot)org |
Subject: | Re: pgsql/src/backend/nodes (copyfuncs.c outfuncs.c print.c) |
Date: | 2000-10-27 04:31:20 |
Message-ID: | 39F90518.F7A206C4@tpf.co.jp |
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Lists: | pgsql-committers pgsql-hackers |
Tom Lane wrote:
> Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp> writes:
> > begin;
> > declare myc cursor for select * from t1 limit all;
> > fetch 20 in myc; (the first page)
> > ...(interaction)
> > fetch 20 in myc; (the next page)
> > ..(interaction)
> > fetch backward 20 in myc; (the previous page)
> > ...
>
> > What I expect here is to get rows of each page in
> > an average response time not the total throughput
> > of db operation.
>
> Yes, but why should the presence of "limit all" affect that?
> It's not apparent to me why the optimizer should treat this
> case differently from plain
> declare myc cursor for select * from t1;
>
Am I misunderstanding ?
Doesn't optimizer make the plan for the query
"select * for t1" which would use SeqScan
in most cases ?
Regards, Hiroshi Inoue
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