Hello list, Following up from the bug that was successfully resolved last week (http://trac.osgeo.org/postgis/ticket/469), I've found that nested loop joins are actually causing very bad performance with my queries.
Thanks to the observations of Leo and Regina in that discussion, I have found that I can work around this by setting enable_nestloop = off. Once that is specified, queries start working about as fast. With enable_nestloop = on, a query may take ~15000 ms, while enable_nestloop = off returns the same query in ~90 ms. I have attached a textfile showing the different 'explain analzye' results for the full query with/without nestloop enabled. You could also refer to the somewhat simplified queries I put together in discussion thread related to bug #469 (see http://postgis.refractions.net/pipermail/postgis-users/2010- March/026235.html for some examples). Is this something that should be looked into, or should I just incorporate the workaround of disabling nested loop joins into my code? Thanks, Mike _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
