On 2020-06-25 09:24:52 -0700, Jeff Davis wrote: > On Wed, 2020-06-24 at 12:14 -0700, Andres Freund wrote: > > E.g. if the plan isn't expected to spill, > > only spill at 10 x work_mem or something like that. > > Let's say you have work_mem=32MB and a query that's expected to use > 16MB of memory. In reality, it uses 64MB of memory. So you are saying > this query would get to use all 64MB of memory, right? > > But then you run ANALYZE. Now the query is (correctly) expected to use > 64MB of memory. Are you saying this query, executed again with better > stats, would only get to use 32MB of memory, and therefore run slower?
Yes. I think that's ok, because it was taken into account from a costing perspective int he second case.
