Re: COMMIT stuck for days after bulk delete

Josh Kupershmidt <schmiddy(at)gmail(dot)com> writes:
> We have a 9.1.11 backend (Ubuntu 12.04 x86_64, m1.medium EC2 instance)
> which seems to be stuck at COMMIT for 2 days now:
> ...
> The transaction behind that COMMIT has been the only thing running on
> this Postgres instance for the past 3 days or so, since Postgres was
> started on that machine. I spun the EC2 instance for this database up
> solely to test a database subsetting process, which is what the
> transaction was doing before it got stuck at COMMIT -- using a bunch
> of DELETEs and ALTER TABLE ... DROP|ADD CONSTRAINTs to delete 90% or
> so of our data in order to be able to pg_dump a slimmed-down
> development copy.

A plausible guess is that the backend is running around trying to verify
that some deferred foreign key constraints still hold. But without
knowing what your schema is, that's only a guess.

If that is it, a likely solution is to drop *all* the FK constraints
before doing the bulk delete, then (in a new transaction, probably)
recreate the ones you still want.

regards, tom lane