On Mon, Sep 27, 2010 at 8:50 PM, Dave Crooke <dcrooke@gmail.com> wrote:
Our Java application manages its own schema. Some of this is from Hibernate, but some is hand-crafted JDBC.
By way of an upgrade path, we have a few places where we have added additional indexes to optimize performance, and so at startup time the application issues "CREATE INDEX ..." statements for these, expecting to catch the harmless exception "ERROR: relation "date_index" already exists", as a simpler alternative to using the meta-data to check for it first.
In general, this seems to work fine, but we have one installation where we observed one of these CREATE statements hanging up in the database, as if waiting for a lock, thus stalling the app startup
You can tell if it is really waiting by looking at 'select * from pg_locks', and check the 'granted' column.
it's PG 8.4.4 64-bit on RHEL 5, installed with the postgresql.org YUM repository.
Stopping and restarting PG did not clear the issue. While this is going on, the database is otherwise responsive, e.g. to access with psql.
Also check if you have any prepared transactions waiting to be committed or rolled back.
select * from pg_prepared_xacts
Is this "expected failure" considered a dangerous practice in PGSQL and should we add checks?
Does the hangup indicate a possible corruption problem with the DB?
