On Fri, Oct 03, 2003 at 05:44:49PM -0400, Rod Taylor wrote: > > item_max_date() looks like this: > > select max(dtstamp) from items where channel = $1 and link = $2; > > It is too bad the (channel, link) index doesn't have dtstamp at the end > of it, otherwise the below query would be a gain (might be a small one > anyway). > > select dtstamp > from items > where channel = $1 > and link = $2 > ORDER BY dtstamp DESC > LIMIT 1;
Similar idea to what Josh suggested. I did create an additional index with dtstamp at the end and it doesn't look like the planner used it. Using the above query instead of max() didn't improve things either. > > > Could you show us the exact specification of the function? In > particular, did you mark it VOLATILE, IMMUTABLE, or STABLE? > > I hope it isn't the first or second one ;) CREATE or REPLACE FUNCTION item_max_date (int4, varchar) RETURNS timestamptz AS ' select max(dtstamp) from items where channel = $1 and link = $2; ' LANGUAGE 'sql'; -- Dror Matalon Zapatec Inc 1700 MLK Way Berkeley, CA 94709 http://www.zapatec.com ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
