Oracle Database - Trace File 10053 to understand the Optimizer (CBO)
1 - About
The reason for examining a 10053 is typically to understand why the CBO made its decisions. The 10053 will help answer the question:
- “Why was my index not used?” or the related,
- “Why did the CBO choose an FTS?”.
The 10053 is typically not the best place to start looking for tuning opportunities:
have better information in this regard.
The 10053 is used for deeper cause determination.