Improve performance of On-line object tree build in RC/Migrator

Products

• RC/Migrator for DB2 for z/OS
• RC Compare for DB2 for z/OS

Issue/Introduction

The object tree is used in an RC/Migrator for Db2 for z/OS (RCM) session when creating or updating strategies. It contains only relationship information used to traverse from one object to another.

• Occurs for Compares (target and source) and Migrations, but not Alters
  
  
• Occurs ONCE per subsystem, per RCM session (unless the same subsystem is referenced multiple times, with other subsystems being referenced in between)
  
  
• Is built only upon first Strategy Create or Strategy Update (per subsystem, per session)

Resolution

These are some performance guidelines to improve online tree build performance:

• VSAM Reads will help performance (pre DB2 v8 only)
  
  
• ACM(Alternate Catalog Mapping) will help performance
  Note: VSAM Reads cannot be used in conjunction with ACM
  
  
• Reorging the strategy tables will not boost performance of online tree build
  
  
• Additional catalog indexes will not help performance of online tree build because where clauses are not used
  
  
• FULLTREE yes/no does not affect the online tree build