Ok, but this is really my problem: I cannot perform an ALTER TABLE with the system in production mode, because the ALTER TABLE hangs due an AccessShareLock.
We use two-tier mode, so is it necessary to shutdown all users before perform an ALTER TABLE? Is it this true? Thanks, Clayton 2009/12/19 Jaime Casanova <jcasa...@systemguards.com.ec> > On Sat, Dec 19, 2009 at 9:04 AM, Clayton Graf <clayton.g...@gmail.com> > wrote: > > I get an AccessShareLock in a simple select command and I am not using > the > > FOR SHARE clause. > > http://www.postgresql.org/docs/current/static/explicit-locking.html says: > """ > ACCESS SHARE > > Conflicts with the ACCESS EXCLUSIVE lock mode only. > > The SELECT command acquires a lock of this mode on referenced > tables. In general, any query that only reads a table and does not > modify it will acquire this lock mode. > """ > in other words, everything is ok, AccessShareLock doesn't block > anything but with anyone trying to change the structure of the table > (ALTER, DROP) and with commands TRUNCATE, REINDEX, CLUSTER, and VACUUM > FULL, and every select take it > > -- > Atentamente, > Jaime Casanova > Soporte y capacitación de PostgreSQL > AsesorÃa y desarrollo de sistemas > Guayaquil - Ecuador > Cel. +59387171157 > -- Clayton Graf
