ALTER TABLE LOCK DISABLE

From: Wolfson Larry - lwolfs <lawrence.wolfson_at_acxiom.com>
Date: Fri, 25 Mar 2005 13:27:18 -0600
Message-ID: <B39B7B7D8C8CEA419D0ED45FD7FA4C5331CAB4@CWYMSX06.Corp.Acxiom.net>

Recently, Tanel Poder had suggested a way to reduce locks and latching was to issue a:

ALTER TABLE owner.table LOCK DISABLE.

This stops checking for table locks and also stops anyone from dropping or altering a table. He said this was particularly beneficial in RAC environments.

The day before yesterday at Danny Dunn's RAC presentation he mentioned the same thing was in 9i R1 RAC Performance doc. See item 3 below

from VERITAS TECH day at Westin O'Hare CHICAGO 3/23

      RAC tuning tips


*          Physical table and index partitioning

*          Index isolation and distribution access strategies

*          Disable table level locks

*          Eliminate run-time DDL

*          Use read-only tablespaces

*          Use locally managed tablespaces

*          Use automatic segment space management

*          Cache sequences

*          Appropriate block size and pctfree

*          DB_MULTI_BLOCK_READ_COUNT parameter

*          Use Automatic Workload Management

Danny said the performance info was not on the R2 doc.

	Anyone have measurable improvements using this technique?
	Any problem doing this with purchased apps?

	We run 100s of databases and apps and I only remember one that

temporarily issued a significant number of table locks. Which, of course, they complained about when multiple users started to butt heads.

Larry

The information contained in this communication is confidential, is intended only for the use of the recipient named above, and may be legally privileged. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited.
If you have received this communication in error, please re-send this communication to the sender and delete the original message or any copy of it from your computer system. Thank You.

--
http://www.freelists.org/webpage/oracle-l

Received on Fri Mar 25 2005 - 14:30:59 CST