StarQuest Technical Documents

Best Practices for Restoring or Migrating a Database Monitored by SQDR Plus for UDB

Last Update: 28 April 2008
Product: SQDR Plus for UDB
Version: 3.0 or later
Article ID: SQV00PU003

Abstract

Restoring or migrating a database that is currently being monitored by SQDR Plus may result in higher than normal CPU usage on the UDB system. The high CPU usage results from the journal receiver processing that must occur after the database is restored.

This document describes a technique that will help minimize the processing required after restoring or migrating a database that is being monitored by SQDR Plus. The procedures described below cause SQDR to run baseline replications of all the incremental replication subscriptions instead of processing all the journal receivers produced by the restore operation. This is much more efficient than allowing incremental replication changes to be applied after the entire database is replaced and will result in much less CPU utilization.

Solution

Prior to restoring the database on the iSeries:

1. Using the SQDR Replication Manager on the Windows system running SQDR, pause the Incremental Replication Group(s) by right-clicking the Group(s) and selecting Pause. Alternatively, you may stop the SQDR service from the SQDR Replication Manager or from Windows Services.
2. On the UDB system, stop the SQDRPlus service from Windows Services.
3. On the UDB system, open a DB2 command line processor window (DB2 CLP). 
4. Connect to the database that is being monitored by SQDR Plus using the command:

connect to <database name>

5. Execute the following SQL statement:

delete from sqdr.sq_readers

Upon successful completion, end the session with the quit command and exit the CLP window.

After restoring the database on the UDB system:

6. On the UDB system, start the SQDRPlus service from Windows Services.
7. If you chose to stop the SQDR Service on the Windows system in Step 1, restart it. If you Paused the Incremental Replication Groups in Step 1, resume them by right-clicking the Group(s) and selecting Resume.