FW: Truncate table - interaction with a long running query
- From: "Baumgartel, Paul" <paul.baumgartel@xxxxxxxxxxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Wed, 15 Aug 2007 21:44:53 +0100
Mea culpa. My earlier post about queries and DDL confused parse locks with row
locks. A query holds no locks at all. I really have to resist the impulse to
answer questions quickly without confirming the accuracy of what I'm about to
say.
Parse locks, from the Concepts manual:
A SQL statement (or PL/SQL program unit) in the shared pool holds a parse lock
for each schema object it references. Parse locks are acquired so that the
associated shared SQL area can be invalidated if a referenced object is altered
or dropped. A parse lock does not disallow any DDL operation and can be broken
to allow conflicting DDL operations, hence the name breakable parse lock.
A parse lock is acquired during the parse phase of SQL statement execution and
held as long as the shared SQL area for that statement remains in the shared
pool.
Paul Baumgartel
CREDIT SUISSE
Information Technology
Securities Processing Databases Americas
One Madison Avenue
New York, NY 10010
USA
Phone 212.538.1143
paul.baumgartel@xxxxxxxxxxxxxxxxx
www.credit-suisse.com
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