On Mon, Aug 23, 2021 at 10:46 AM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > On Thu, Aug 19, 2021 at 10:52 PM Ranier Vilela <ranier...@gmail.com> wrote: > > > > Em qui., 19 de ago. de 2021 às 09:21, Masahiko Sawada > > <sawada.m...@gmail.com> escreveu: > >> > >> Hi all , > >> > >> It's reported on pgsql-bugs[1] that I/O timings in EXPLAIN don't show > >> the one for temp files. I think it's not a bug but could be an item > >> for PG15. As mentioned on that thread, this would be useful for users > >> in a case where temp buffers I/O used most of the time. So I've > >> written the patch for that. Please note that the patch includes only > >> to show temp buffer I/O timing to EXPLAIN but not other possibly > >> related changes such as pg_stat_statement improvements yet. > >> > >> Before (w/o patch): > >> postgres(1:14101)=# explain (analyze, buffers) select count(*) from > >> generate_series(1,100000); > >> QUERY PLAN > >> ----------------------------------------------------------------------------------------------------------------------------------- > >> Aggregate (cost=1250.00..1250.01 rows=1 width=8) (actual > >> time=59.025..59.026 rows=1 loops=1) > >> Buffers: temp read=171 written=171 > >> -> Function Scan on generate_series (cost=0.00..1000.00 > >> rows=100000 width=0) (actual time=21.695..45.524 rows=100000 loops=1) > >> Buffers: temp read=171 written=171 > >> Planning Time: 0.041 ms > >> Execution Time: 70.867 ms > >> (6 rows) > >> > >> After (w/ patch): > >> postgres(1:28754)=# explain (analyze, buffers) select count(*) from > >> generate_series(1,100000); > >> QUERY PLAN > >> ----------------------------------------------------------------------------------------------------------------------------------- > >> Aggregate (cost=1250.00..1250.01 rows=1 width=8) (actual > >> time=56.189..56.190 rows=1 loops=1) > >> Buffers: temp read=171 written=171 > >> I/O Timings: temp read=0.487 write=2.073 > >> -> Function Scan on generate_series (cost=0.00..1000.00 > >> rows=100000 width=0) (actual time=21.072..42.886 rows=100000 loops=1) > >> Buffers: temp read=171 written=171 > >> I/O Timings: temp read=0.487 write=2.073 > >> Planning Time: 0.041 ms > >> Execution Time: 59.928 ms > >> (8 rows) > >> > >> Feedback is very welcome. > > > > Thank you for the comments! > > > The presentation seems a little confusing, wouldn't it be better? > > > > I/O Timings: shared/local read=xxxx write=xxx temp read=0.487 write=2.073 > > Yeah, it looks better to add "shared/local".
I've attached the updated patch that incorporates the above comment. Regards, -- Masahiko Sawada EDB: https://www.enterprisedb.com/
v2-0001-Track-I-O-timing-for-temp-buffers.patch
Description: Binary data
