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*. ---------------------------------------------------------------- Philip Warner | __---_____ Albatross Consulting Pty. Ltd. |----/ - \ (A.B.N. 75 008 659 498) | /(@) ______---_ Tel: (+61) 0500 83 82 81 | _________ \ Fax: (+61) 0500 83 82 82 | ___________ | Http://www.rhyme.com.au | / \| | --________-- PGP key available upon request, | / and from pgp5.ai.mit.edu:11371 |/
