Re: backends stuck in "startup"

On 2017-11-21 18:21:16 -0500, Tom Lane wrote:
> Justin Pryzby <pryzby(at)telsasoft(dot)com> writes:
> > As $subject: backends are stuck in startup for minutes at a time. I didn't
> > strace this time, but I believe last time I saw one was waiting in a futex.
>
> Hm...

A futex? Hm, that was stock postgres?

> > I saved ~40 cores from backends from the most recent incident, which are all
> > essentially identical:
>
> This one seems to be waiting for a shared LWLock (specifically, one of
> the locks for the shared-buffer lookup hashtable), which could only block
> if someone else is holding that lock exclusively, which implies that
> there's at least one backtrace that's different from this.

Hm. Wonder if that implies that there's a lot of cache pressure, or
whether it's the compounded amount of

How many different databases and roles are you having on that system? I
guess iiiiiii is a sanitized name?

Greetings,

Andres Freund