After Gathering System Stats and after Upgrade to 10g Shows High Value for IOTFRSPEED From 10053 Causing CBO To Choose Bad Expensive Plan
Last updated on SEPTEMBER 15, 2016
Applies to:Oracle Database - Enterprise Edition - Version 10.2.0.1 to 184.108.40.206 [Release 10.2 to 11.2]
Information in this document applies to any platform.
This problem can occur on any platform.
- A statement can be very slow on 10g compared to 9i after gathering system statistics using dbms_stats.set_system_stats
- 10053 trace shows that IOTFRSPEED is of very high after gathering system stats
- This high value deceives the CBO causing more I/Os (especially in FTS)
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