Re: Possible bugreport 8.3 beta1 on Win32: Looking like a deadlock with AutoVacuum - Mailing list pgsql-hackers

Deblauwe Gino wrote:
> OS: Windows XP Pro SP2
> CPU: AMD Athlon 64 3500+
> RAM: 2GB
> DB: PostgreSQL 8.3beta1, compiled by Visual C++ build 1400
>
> I've come to the conclusion that it seems like a deadlock occurs when 
> dropping a column in a table the same moment that table is autovacuumed.
>
> Example:
>
> ALTER TABLE bondetail DROP COLUMN btw; (user=gino, 16252 records)
> deadlocks with
> VACUUM ANALYZE public.bondetail; (user=postgres)

Does it really deadlock, or is it just locked waiting for the vacuum to
finish?

If it deadlocks you should get a message about it and a transaction
rollback.  Otherwise you should be able to see the ungranted lock in
pg_locks.

Also it's not clear if autovacuum is involved, or you invoked the VACUUM
ANALYZE manually.  Can you clarify?

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.