SQL/MP Installation and Management Guide

Planning Database Security and Recovery
HP NonStop SQL/MP Installation and Management Guide—523353-004
4-16
TMF Considerations in Using SQLCI
objects. Thus, if a file recovery is necessary your online dumps already reflect the
batch updates. TMF would need to apply only those database changes that
occurred after the online dumps were taken.
•
When you create a new table and you want to provide file recovery protection for
the table, you should make an initial online dump of the file after creating it.
•
Certain DDL statements invalidate previous online dumps. For instance, whenever
you load tables, upgrade catalogs, create new indexes, partition tables or indexes,
or restructure or move the database, you should always make new online dumps to
ensure the new status of the database is recorded correctly.
For more information, see Operations That Invalidate TMF Online Dumps on
page 11-15.
•
Operations that use the WITH SHARED ACCESS option allow you to take online
dumps while the operations are running.
•
The TMF catalog can retain online dumps of several generations of each file. The
number of generations retained depends on the RETAINDEPTH option of the TMF
configuration parameters. Each generation of an online dump provides a starting
point for a file recovery operation. You gain greater reliability by keeping extra
generations of online dumps, but the site needs additional tape management for
the online dumps and audit trails.
For additional information about TMF recovery operations, see the TMF Operations
and Recovery Guide.
TMF Considerations in Using SQLCI
You can define and manage transactions from SQLCI, as follows:
•
For DML statements, SQLCI generates TMF transactions for individual statements
if the AUTOWORK session option is set to ON. If you set AUTOWORK to OFF,
disabling automatic transaction generation for DML statements, you must explicitly
begin and end TMF transactions in the SQLCI session. The SQL statements that
explicitly control transactions are BEGIN WORK, COMMIT WORK, and
ROLLBACK WORK. AUTOWORK ON is the default.
•
With AUTOWORK set to either ON or OFF, you can explicitly define a TMF
transaction, also called a user-defined TMF transaction. You can use a user-
defined TMF transaction to ensure that several statements are either all executed
successfully or all rolled back.
These commands and statements make up a complete user-defined TMF
transaction:
>> BEGIN WORK;
>> SELECT .....;
>> INSERT .....;
>> DELETE .....;
>> COMMIT WORK;