Query Execution Plan Changed After UpgradingDG4DRDA From 18.104.22.168 To 22.214.171.124 Causing Increased Execution Times
Last updated on DECEMBER 11, 2014
Applies to:Oracle Database Gateway for DRDA - Version 126.96.36.199 to 188.8.131.52 [Release 11.2 to 12.1]
Information in this document applies to any platform.
The query execution plan for a particular query against several DB2 tables changed after upgrading the Database Gateway for DRDA (DG4DRDA) from 184.108.40.206 to 220.127.116.11.
After the gateway upgrade the SQL against the DB2 tables had a different execution plan -
- In 18.104.22.168, the execution plan sent a complete query to DB2 for all the tables and results were returned in 30 minutes
- In 22.214.171.124, the execution plan causes queries against individual DB2 tables on the DB2 side. There is then join made on the Oracle side of the individual table results. Because the underlying DB2 tables are large, the query now runs for over 4 hrs.
- In 126.96.36.199 and 188.8.131.52 you can receive the ORA-28501: communication error on heterogeneous database link
Sign In with your My Oracle Support account
Don't have a My Oracle Support account? Click to get started
My Oracle Support provides customers with access to over a
Million Knowledge Articles and hundreds of Community platforms