> See: > http://www.postgresql.org/docs/8.3/interactive/explicit-locking.html > > where it says that ALTER TABLE obtains the ACCESS EXCLUSIVE lock. You > can confirm this by issuing the command of interest then running: > > SELECT * from pg_catalog.pg_locks; > > With that transaction still open, and that lock still held, you then > execute a new process (pg_restore) that establishes its own unrelated > connection to the database and tries to get a ROW EXCLUSIVE lock (if > using INSERT, and presumably COPY though the docs don't say so) on the > table. It can't do so, because your Java program holds an ACCESS > EXCLUSIVE lock on the table that conflicts with the requested lock mode. > > Your java code won't release the lock until pg_restore finishes, and > pg_restore won't finish until your java code releases the lock. > > Deadlock. > > > There is no way you can "pass" your connection to pg_restore when you > invoke it from Java. Thus, you must either not hold any locks that would > prevent pg_restore from acting on the table, or you must do all the work > within Java using your existing JDBC connection.
This is exactly what I was trying to make it clear to myself. Thank you Craig! -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
