StarQuest Technical Documents

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

Last Update: 28 April 2008
Product: SQDR Plus for iSeries
Version: 3.0 or later
Article ID: SQV00PL003

Abstract

Restoring or migrating a database that is currently being monitored by SQDR Plus may result in higher than normal CPU usage on the iSeries 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 iSeries, stop the SQDR subsystem using the OS400 command:

    ENDSBS SBS(SQDR) OPTION(*CNTRLD)

  3. On the iSeries, start an interactive SQL session using the OS400 command STRSQL. Check the session defaults for the object naming convention using CMD KEY 13. The output will display the parameter value that indicates the type of naming convention supported (either “*SQL” or “*SYS”).
  • If using “*SQL” style naming convention, execute the following statement:

    DELETE FROM SQDR.SQ_READERS

  • If using the “*SYS” style naming convention, execute the following statement:

DELETE FROM SQDR/SQ_READERS

Upon successful completion, end the session and exit the interactive SQL session using CMD KEY 3.

After restoring the database on the iSeries:

  1. On the iSeries, start the SQDR subsystem using the OS400 command:

    STRSBS SBSD(SQDR/SQDR)

  2. 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.

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