Re: Major pgbench synthetic SELECT workload regression, Ubuntu 23.04+PG15

On Fri, Jun 9, 2023 at 4:06 AM Gurjeet Singh <gurjeet(at)singh(dot)im> wrote:

> There is no mention of perf or similar utilities in pgbench-tools
> docs. I'm guessing Linux is the primary platform pgbench-tools gets
> used on most. If so, I think it'd be useful to mention these tools and
> snippets in there to make others lives easier.

That's a good idea. I've written out guides multiple times for customers
who are crashing and need to learn about stack traces, to help them becomes
self-sufficient with the troubleshooting parts it's impractical for me to
do for them. If I can talk people through gdb, I can teach them perf. I
have a lot of time to work on pgbench-tools set aside this summer, gonna
finally deprecate the gnuplot backend and make every graph as nice as the
ones I shared here.

I haven't been aggressive about pushing perf because a lot of customers at
Crunchy--a disproportionately larger number than typical I suspect--have
operations restrictions that just don't allow DBAs direct access to a
server's command line. So perf commands are just out of reach before we
even get to the permissions it requires. I may have to do something really
wild to help them, like see if the right permissions setup would allow
PL/python3 or similar to orchestrate a perf session in a SQL function.