How to look for access path change?

Products

• RC Compare for DB2 for z/OS
• Bind Analyzer for DB2 for z/OS
• SQL-Ease for DB2 for z/OS
• SYSVIEW Performance Management Option for DB2 for z/OS
• Plan Analyzer for DB2 for z/OS
• Subsystem Analyzer 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

Issue/Introduction

Description:

Does plan analyzer have the ability to look at the existing packages and determine changes to access path (good or bad) without actually doing the rebind?

Solution:

Yes, Plan analyzer does that with the FUTURE EXPLAIN which shows you the impact of rebinding a plan package. A Future Explain executes a dynamic EXPLAIN command and then uses information from the DB2 Optimizer, catalog statistics, and Unicenter Plan Analyzer Expert System Rules. The Future Explain tells you your access paths when you request a bind right now.

To specify that you want to do a future explain, you need the following steps:

• Select option 1) Quick Explain or 2) EXPLAIN Strategy Services to create a Strategy.
  
  
• Type E besides your strategy if you selected option 2 to explain it.
  
  
• Turn the Update Explain Options ===> Y in the PPA Explain Strategy - Version Info.
  
  
• Set Explain Type ===> F in PPA Explain Strategy - Explain Options to indicate you want Future Explain.

Environment

Release:
Component: PPADB2