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execution-plan

I ‘fixed’ execution plan regression with optimizer_features_enable, what to do next?

Here is a simple example of using Mauro Pagano ‘pathfinder’ tool where you don’t really want to run the query, but just get the execution plan with all variations of optimizer settings. That’s something I used many times in situations similar to this one:

Oracle Adaptive Plan info in OTHER_XML

DBMS_XPLAN displays the operation ID with no gap, even for Adaptive Plans where the inactive operations are skipped. Did you ever wonder where the information of skipped rows is stored?

Here is a simple query (but please, remember that natural join is bad ;)

SQL> set feedback on sql_id
SQL> select * from dept natural join emp natural join bonus;
no rows selected
SQL_ID: 3q7fbwk91v4ra

The execution plan shows that the plan is adaptive: