all,
I am learning to tune query now, when I ran the following:
select /*+ gather_plan_statistics */ * from emp;
select * from table(dbms_xplan.display(FORMAT=>'ALLSTATS LAST'));
The result always says:
- Warning: basic plan statistics not available. These are only collected when:
- hint 'gather_plan_statistics' is used for the statement or
- parameter 'statistics_level' is set to 'ALL', at session or system level
I tried the alter session set statistics_level = ALL;
too in sqlplus, but that did not change anything in the result.
Could anyone please let me know what I might have missed?
Thanks so much.
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