Re: VACUUM FULL hangs on ordinary table

"Ivan Zolotukhin" <ivan(dot)zolotukhin(at)gmail(dot)com> writes:
> When I run VACUUM FULL VERBOSE ANALYZE it processes several
> tables/indexes and than hangs (at least I tried to wait for 30 mins
> and nothing happened) on one particular table "education" which is
> quite ordinary I think. When it hangs I see in `ps auxww` process with
> "VACUUM waiting" in its status.

It's definitely waiting for a lock then.

> Below I pasted last lines concerning above table from VACUUM output
> (it stops after the last line):
> ...
> INFO: analyzing "public.education"
> INFO: "education": scanned 674 of 674 pages, containing 40653 live
> rows and 1111 dead rows; 3000 rows in sample, 40653 estimated total
> rows

If it hangs there then I'd venture that it's trying to get writer's
lock (RowExclusiveLock) on pg_statistic so it can store the new
statistic rows. Or possibly pg_class. You should be looking for locks
on the system catalogs not locks on "education" itself.

regards, tom lane