On Monday, December 20, 2021, Justin Pryzby <pry...@telsasoft.com> wrote:
> On Mon, Dec 20, 2021 at 08:11:42PM -0800, Lars Bergeson wrote: > > ok, here are results after I did: > > set max_parallel_workers_per_gather = 0; > > > > HashAggregate (cost=1676432.13..1676432.16 rows=3 width=15) (actual > time=19908.343..19908.345 rows=5 loops=1) > > I/O Timings: read=532369.898 > > Execution Time: 19908.383 ms > > > HashAggregate (cost=1390580.70..1390580.72 rows=2 width=15) (actual > time=30369.758..30369.761 rows=5 loops=1) > > I/O Timings: read=6440851.540 > > Execution Time: 30369.796 ms > > > Still taking 10X more I/O to read the smaller table. Very odd. > > If I'm not wrong, it's even worse than that ? > It takes 20 or 30sec to run the query - but it says the associated I/O > times > are ~500sec or ~6000sec ? > > What architecture and OS/version are you running ? > How did you install postgres? From a package or compiled from source ? > The docs indicate you’ll only see I/O Timing information if using EXPLAIN BUFFERS but I’m not seeing any of the other buffer-related information in these plans. Thoughts? David J.
