Examine this command:
SQL > exec DBMS_STATS.SET_TABLE_PREFS (‘SH’, ‘CUSTOMERS’, ‘PUBLISH’, ‘false’);
Which three statements are true about the effect of this command?
A.
Statistics collection is not done for the CUSTOMERS table when schema stats are gathered.
B.
Statistics collection is not done for the CUSTOMERS table when database stats are gathered.
C.
Any existing statistics for the CUSTOMERS table are still available to the optimizer at parse
time.
D.
Statistics gathered on the CUSTOMERS table when schema stats are gathered are stored as
pending statistics.
E.
Statistics gathered on the CUSTOMERS table when database stats are gathered are stored as
pending statistics.
Explanation:
* SET_TABLE_PREFS Procedure
This procedure is used to set the statistics preferences of the specified table in the specified
schema.
* Example:
Using Pending Statistics
Assume many modifications have been made to the employees table since the last time statistics
were gathered. To ensure that the cost-based optimizer is still picking the best plan, statistics
should be gathered once again; however, the user is concerned that new statistics will cause the
optimizer to choose bad plans when the current ones are acceptable. The user can do thefollowing:
EXEC DBMS_STATS.SET_TABLE_PREFS(‘hr’, ’employees’, ‘PUBLISH’, ‘false’);
By setting the employees tables publish preference to FALSE, any statistics gather from now on
will not be automatically published. The newly gathered statistics will be marked as pending.
Not agree!
By setting tables publish preference to FALSE, any statistics gather from now on will not be automatically published. The newly gathered statistics will be marked as pending. Statistic collection is STILL done when both schema stats and database stats are gathered, just pending, no publishing.
So CDE
Any opinion?
I think you’re right, CDE
C D E it is indeed.
When I gathered schema and database level I don’t find any pending stats but when you gather the table stats I can see pending status and one record in the pending stats table. It looks ABC is correct
CDE
CDE