Thanks Rod, This setting has no effect however. If I set statistics to 1000, or even 0, (and then reanalyze the table) I see no change in the behaviour of the query plans. i.e. there is still the odd transtion in the plans at diagonalSize = 50.
Ken On Wed, 2004-06-09 at 13:12, Rod Taylor wrote: > It seems to believe that the number of rows returned for the >49.999 > case will be 4 times the number for the >50 case. If that was true, then > the sequential scan would be correct. > > ALTER TABLE <table> ALTER COLUMN diagonalsize SET STATISTICS 1000; > ANALZYE <table>; > > Send back EXPLAIN ANALYZE output for the >49.999 case. > > > The query plan for diagonalSize > 50.000 is ... > > > > Index Scan using nrgfeature_xys_index on nrgfeature f > > (cost=0.00..17395.79 rows=4618 width=220) > > Index Cond: ((upperrightx > 321264.236977215::double precision) AND > > (lowerleftx < 324046.799812083::double precision) AND (upperrighty > > > 123286.261898636::double precision) AND (lowerlefty < > > 124985.927450476::double precision) AND (diagonalsize > 50::double > > precision)) > > > > ... while for diagonalSize > 49.999 is ... > > > > Seq Scan on nrgfeature f (cost=0.00..31954.70 rows=18732 width=220) > > Filter: ((upperrightx > 321264.236977215::double precision) AND > > (lowerleftx < 324046.799812083::double precision) AND (upperrighty > > > 123286.261898636::double precision) AND (lowerlefty < > > 124985.927450476::double precision) AND (diagonalsize > 49.999::double > > precision)) > > > ---------------------------(end of broadcast)--------------------------- > TIP 9: the planner will ignore your desire to choose an index scan if your > joining column's datatypes do not match > ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly