Justin, Thanks for your continued interest.
I'm running PostgreSQL under AWS Aurora, and I didn't set it up or install it, so I'm not sure about the OS version. I can't run the grep command since I don't know how to get down to the command line on the actual box running Aurora. I just connect to PostgreSQL from either my desktop or an EC2 Linux instance. SQL I entered was: set max_parallel_workers_per_gather = 0; explain (analyze, buffers, settings) select roys_creation_user, count(*) from eu.royalty_with_null group by roys_creation_user; The output is shown earlier in this thread. I have no idea why I have IO timings but not buffers hit/read. On Tue, Dec 21, 2021 at 1:13 PM Justin Pryzby <pry...@telsasoft.com> wrote: > On Tue, Dec 21, 2021 at 12:33:06AM -0500, Tom Lane wrote: > > So now we have a real mystery about what is happening on Lars' > > system. Those numbers can't be right. > > I realized Lars said it was x86_64/Linux, but I'm hoping to hear back with > more > details: > > What OS version? > Is it a VM of some type ? > How did you install postgres? From a package or compiled from source? > grep -r HAVE_CLOCK_GETTIME /usr/pgsql-13/include > Send the exact command and output you used to run the query? > Why does your explain output have IO timing but not Buffers: hit/read ? > > -- > Justin >
