Hi, > On Wed, 10 Jul 2024 at 21:36, Tatsuo Ishii <is...@postgresql.org> wrote: >> v2-0005-Add-memory-disk-usage-for-Window-Aggregate-nodes-.patch: This >> adds memory/disk usage for Window Aggregate nodes in EXPLAIN (ANALYZE) >> command. Note that if David's proposal >> https://www.postgresql.org/message-id/CAHoyFK9n-QCXKTUWT_xxtXninSMEv%2BgbJN66-y6prM3f4WkEHw%40mail.gmail.com >> is committed, this will need to be adjusted. > > Hi, > > I pushed the changes to WindowAgg so as not to call tuplestore_end() > on every partition. Can you rebase this patch over that change? > > It would be good to do this in a way that does not add any new state > to WindowAggState, you can see that I had to shuffle fields around in > that struct because the next_parition field would have caused the > struct to become larger. I've not looked closely, but I expect this > can be done by adding more code to tuplestore_updatemax() to also > track the disk space used if the current storage has gone to disk. I > expect the maxSpace field can be used for both, but we'd need another > bool field to track if the max used was by disk or memory. > > I think the performance of this would also need to be tested as it > means doing an lseek() on every tuplestore_clear() when we've gone to > disk. Probably that will be dominated by all the other overheads of a > tuplestore going to disk (i.e. dumptuples() etc), but it would be good > to check this. I suggest setting work_mem = 64 and making a test case > that only just spills to disk. Maybe do a few thousand partitions > worth of that and see if you can measure any slowdown.
Thank you for the suggestion. I will look into this. Best reagards, -- Tatsuo Ishii SRA OSS K.K. English: http://www.sraoss.co.jp/index_en/ Japanese:http://www.sraoss.co.jp
