Re: Performance of MERGE INTO statement
Date: Mon, 19 May 2008 08:49:41 +0900
> Finn - I'm not sure why the optimizer thinks that there is only one row.
> I've gathered stats and the NUM_ROWS column shows 3,041,890. There are
> presently two partitions on this table. USER_TAB_PARTITIONS shows that
> one has 1,078 rows and the other has 4,089,540 rows (it's partitioned by
> month and I've been testing it with one month of data).
> * | 20 | TABLE ACCESS FULL | CALL_FACTS | 1 | 66
> | 1358 | KEY | KEY |
You did not post the predicate information. (where call_facts.c1 = ... ) Oracle applied some basic formulars for your predicate and the result was "1"(or 0).
Predicate part of the execution plan is essential when interpreting the cardinality and cost.
Dion ChoReceived on Sun May 18 2008 - 18:49:41 CDT