On Tue, 14 Sep 2004, Robert Davis wrote: > I'm trying to benchmark some complex sql queries. One query, in > particular, is causing problems -- its cost values can vary from 228 > to 907, its Total Runtimes from 60 ms to 5176 ms. The query plans > show that the optimizer is choosing different plans for different > iterations of the same query. Does anyone have any idea what's > going on here or maybe how I can force Postgres to prefer the faster > plan? > > The query plans are very long (11 tables joined) but I can include > them if it might help. Thanks for any advice,
11 tables. You might want to see if raising geqo_threshold stabilizes the plans since IIRC that's the threshold for using the genetic optimizer. ---------------------------(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