Few questions about statistics
Date: Tue, 15 Apr 2008 18:36:15 +0300
In general I know the difference between ANALYZE units in DBMS_UTILITY
and ones in DBMS_STATS. What I lack, it's a couple of details
(particularly in 9.2 if it makes a difference):
- Which exactly are the optimizer statistics (and which isn't)? Because
it's said that DBMS_UTILITY don't gather all what's necessary for CBO, while, on the other hand, DBMS_STATS don't bother with stats not needed for CBO.
- How can I know when the last time ANALYZE from DBMS_UTILITY had been
run on the object and when a unit from DBMS_STATS (e.g. DBMS_STATS.GATHER_TABLE_STATS) had? (They both update dictionary, e.g. DBA_TABLES.LAST_ANALYZED). In fact this is a question whether the CBO sats are up to date and valid.