Re: LIMIT in DECLARE CURSOR: request for comments

At 10:51 31/10/00 +0100, Peter Eisentraut wrote:
>Tom Lane writes:
>
>> 1. If DECLARE CURSOR does not contain a LIMIT, continue to plan on the
>> basis of 10%-or-so fetch
>
>I'd say that normally you're not using cursors because you intend to throw
>away 80% or 90% of the result set, but instead you're using it because
>it's convenient in your programming environment (e.g., ecpg). There are
>other ways of getting only some rows, this is not it.

Yes!

>So I think if you want to make optimization decisions based on cursors
>being used versus a "normal" select, then the only thing you can safely
>take into account is the network roundtrip and client processing per
>fetch, but that might be as random as anything.

Which is why I like the client being able to ask the optimizer for certain
kinds of solutions *explicitly*.

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