> See:> http://www.postgresql.org/docs/8.3/interactive/explicit-locking.html>> where it says that ALTER TABLE obtains
theACCESS 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>
usingINSERT, and presumably COPY though the docs don't say so) on the> table. It can't do so, because your Java program
holdsan ACCESS> EXCLUSIVE lock on the table that conflicts with the requested lock mode.>> Your java code won't release
thelock until pg_restore finishes, and> pg_restore won't finish until your java code releases the lock.>> Deadlock.>>>
Thereis no way you can "pass" your connection to pg_restore when you> invoke it from Java. Thus, you must either not
holdany locks that would> prevent pg_restore from acting on the table, or you must do all the work> within Java using
yourexisting JDBC connection.
This is exactly what I was trying to make it clear to myself.
Thank you Craig!
