Why is the Statistics Maintenance execution frequency being ignored?

Products

• RC Compare for DB2 for z/OS
• Database Analyzer for DB2 for z/OS
• Fast Unload for DB2 for z/OS
• Fast Check for DB2 for z/OS
• Fast Index for DB2 for z/OS
• Rapid Reorg for DB2 for z/OS
• CA Distributed Database Management
• CA Database Analyzer for DB2 for Oracle
• Database Analyzer (IMS Tools)
• Mainframe Configuration Manager for IMS for z/OS
• IMS TOOLS - MISC
• Compress Data Compression (IMS Tools)
• Database Analyzer for IMS for z/OS
• Database Copier for IMS for z/OS
• Database Organizer for IMS for z/OS
• Mainframe Extended Terminal Manager (IMS Tools)
• High Performance Recovery for IMS for z/OS
• Database Organizer (IMS Tools)
• Mainframe Program Restart Manager for IMS for z/OS
• Secondary Index Builder for IMS for z/OS
• Secondary Index for IMS for z/OS

Issue/Introduction

Description:

From the PDA Main Menu option 3) Statistics Maintenance, Then option 1) Automatic Statistics Deletion
you can see : AUTOMATIC STATISTICS DELETION panel details as follows:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Last Execution: yyyy/mm/dd  hh:mm:ss   Last Update: yyyy/mm/dd  hh:mm:ss
    by User ID: userid                 by User ID: userid             
                                                                        
Auto-Statistics Activation ==> Y       (Y)es, (N)o, (U)pdate            
                                                                        
  Subsystem Connection ID  ==> ssid                                     
  Location                 ==> LOCAL                                    
                                                                        
  Execution Frequency      ==> nnn  Days     Next Execution: yyyy/mm/dd
  Purge Stats Older Than   ==> nnn  Days                                
                                                                        
  Save Latest Stats for Each Object ==> N           (Y)es, (N)o         
  - Save Latest Stats Every x Days  ==> 000  Days   (0-999)             
  - Ignore Save Latest option when                  'Y'- performance tip
    processing column statistics    ==> Y           (Y)es, (N)o         
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The "Next Execution" date has passed and nothing has been run to clean up the statistics. Why is this?

Solution:

PDA does not automatically start a job on the next execution date. Each time an extract is run, PDA checks the statistics maintenance fields to see if statistics maintenance has been activated ("Y" in Auto-Statistics Activation). If so, it then checks the next execution date to see if it's due.

If it is due, the auto stats maintenance is triggered during that extract processing. Subsequent extracts on the same day will not trigger the Statistics Maintenance, this should only occur once that day (then the next execution date is reset based on options chosen).

Please note: The Statistics Maintenance will not trigger if the extract has the override - MAINT=N on the exec statement. This will cause the statistics maintenance to never run with that extract.

Environment

Release:
Component: DBA