Re: autovacuum stuck on a table for 18+ hours, consuming lots of CPU time

Lonni J Friedman <netllama(at)gmail(dot)com> writes:
> When I strace PID 30188, I see tons of this scrolling past quickly,
> but I'm not really sure what it means beyond a 'Timeout' not looking
> good:
> select(0, NULL, NULL, NULL, {0, 32000}) = 0 (Timeout)
> lseek(95, 753901568, SEEK_SET) = 753901568
> read(95, "\202\1\0\0\260\315\250\245\1\0\0\0\220\0\360\20\360\37\4
> \0\0\0\0p\237\0\1\360\236\0\1"..., 8192) = 8192
> lseek(95, 753917952, SEEK_SET) = 753917952
> read(95, "\202\1\0\0 N\253\245\1\0\0\0\220\0\360\20\360\37\4
> \0\0\0\0p\237\0\1\360\236\0\1"..., 8192) = 8192
> select(0, NULL, NULL, NULL, {0, 32000}) = 0 (Timeout)

I'm betting the selects are implementing vacuum_cost_delay, and that
the reason this is taking forever is that you have that cranked up
to an unreasonably high value. There's no evidence of looping in
what you showed us, because the seek addresses are changing.

regards, tom lane