Hi Tom, Tom Lane wrote: > Bosco Rama <postgres@xxxxxxxxxxxxx> writes: >> I have a strange disparity between a query that is run as a >> straight select and the same query via a cursor. I hope I can >> jog someone's memory with the description as I have been unable >> to create a sanitized and/or reduced data set & schema that will >> reproduce this ... so far. :-( > > Cursors are biased towards fast-start plans on the theory that you > may not be intending to fetch the whole result. Queries with ORDER BY > and/or LIMIT are particularly likely to see plan changes as a > consequence of that. In 8.4 and up you can frob the > cursor_tuple_fraction setting to adjust this preference. Use > "EXPLAIN query" vs "EXPLAIN DECLARE CURSOR FOR query" to see what > sort of plan you're getting. I'll take a look at that setting and try the two 'explain's. However, would that really account for an increase in time by a factor of ~630? Just wondering. (BTW, I'm still working on a public version of the data & schema that reproduce this.) Bosco. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
