Re: Backends "hanging" with strace showing selects?

hubert depesz lubaczewski <depesz@depesz.com> writes:
> hi
> had strange situation today.

> very high load, cpu saturated (and this machine has lots of cores).

> i straced one of backends that was using lots of cpu (it was doing some
> select, but I don't know what as i wasn't able to start psql).

> strace looked like this:
> select(0, NULL, NULL, NULL, {0, 1000})  = 0 (Timeout)
> select(0, NULL, NULL, NULL, {0, 1000})  = 0 (Timeout)
> select(0, NULL, NULL, NULL, {0, 1000})  = 0 (Timeout)
> select(0, NULL, NULL, NULL, {0, 1000})  = 0 (Timeout)

That suggests a lot of contention for a spinlock, but without any
information about what the system was really doing, it's hard to go
further than that.

            regards, tom lane