Nino Arsov <nino.arsov@xxxxxxxxx> writes: > Using EXPLAIN we have successfully managed to get very similar execution > plans and costs by the planner as if there were data in the newly created > partitions. This method works just fine as long as the queries to be > estimated consist of a join of no more than 2 tables. > When we try to estimate a query's cost that contains a join between 3 or > more tables we get huge costs and wrong plans (in the rank of millions of > cost units). When data is actually loaded into all of the partitions, the > cost does not exceed a few thousand cost units. Have you modified the planner at all? Because it's a bit hard to see how inserting faked-up statistics as described would work properly in a 2-way join but not in a 3-way join. A bug in some hack or other would be a much more plausible explanation. I'm also curious about exactly how you're inserting new data into pg_statistic --- the "anyarray" columns that are used there are not readily modifiable from SQL. (This is pretty off-topic for pgsql-admin, btw.) regards, tom lane -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
