RE: [HACKERS] Solution for LIMIT cost estimation

> -----Original Message-----
> From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
>
> Philip Warner  writes:
> >> A possible answer is to define OFFSET/LIMIT in DECLARE CURSOR as
> >> being simply a hint to the optimizer about how much of the query
> >> result will actually get fetched.
>
> > This seems a good approach until cursors are fixed. But is
> there a plan to
> > make cursors support LIMIT properly? Do you know why they
> ignore the LIMIT
> > clause?
>
> Should they obey LIMIT?  MOVE/FETCH seems like a considerably more
> flexible interface, so I'm not quite sure why anyone would want to
> use LIMIT in a cursor.
>

You are right.
What I want is to tell optimizer the hint whether all_rows(total throughput)
is needed or first_rows(constant response time) is needed.

Regards.

Hiroshi Inoue
Inoue@tpf.co.jp