Excerpts from Tom Lane's message of mar jul 27 20:05:02 -0400 2010: > Peter Hussey <peter@xxxxxxxxxx> writes: > > 2) How is work_mem used by a query execution? > > Well, the issue you're hitting is that the executor is dividing the > query into batches to keep the size of the in-memory hash table below > work_mem. The planner should expect that and estimate the cost of > the hash technique appropriately, but seemingly it's failing to do so. > Since you didn't provide EXPLAIN ANALYZE output, though, it's hard > to be sure. Hmm, I wasn't aware that hash joins worked this way wrt work_mem. Is this visible in the explain output? If it's something subtle (like an increased total cost), may I suggest that it'd be a good idea to make it explicit somehow in the machine-readable outputs? -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
