|| at Oct 10, 2007 at 7:02 am
Alvaro Herrera schreef:
Deblauwe Gino wrote:
OS: Windows XP Pro SP2
CPU: AMD Athlon 64 3500+
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.
ALTER TABLE bondetail DROP COLUMN btw; (user=gino, 16252 records)
VACUUM ANALYZE public.bondetail; (user=postgres)
Does it really deadlock, or is it just locked waiting for the vacuum to
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
Also it's not clear if autovacuum is involved, or you invoked the VACUUM
ANALYZE manually. Can you clarify?
No it just looks like a deadlock on first sight. It just takes a very
In this case, it takes 10 minutes instead of 5 seconds to execute the query.
I was only able to reproduce this on 'ALTER TABLE x DROP COLUMN y;'
queries. Those things happen while upgrading
our software to a newer version. The more common instructions
(SELECT/INSERT/UPDATE/DELETE) work fine the same
as adding/changing columns/tables.