Explain Plan explanation
- From: "Brady, Mark" <Mark.Brady@xxxxxxxxxxxxxxxxx>
- To: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 11 Nov 2009 16:44:29 -0500
This is just the top on the plan...
PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------
| Id | Operation | Name |
Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop |
------------------------------------------------------------------------------------------------------------------------------------
| 0 | UPDATE STATEMENT | |
1 | 122 | 6989K (1)| 23:17:57 | | |
| 1 | UPDATE | LSMDMTRDATAREAD |
| | | | | |
|* 2 | FILTER | |
| | | | | |
| 3 | PARTITION RANGE ALL | |
999K| 116M| 5302 (8)| 00:01:04 | 1 | 37 |
| 4 | PARTITION HASH ALL | |
999K| 116M| 5302 (8)| 00:01:04 | 1 | 4 |
| 5 | TABLE ACCESS FULL | LSMDMTRDATAREAD |
999K| 116M| 5302 (8)| 00:01:04 | 1 | 148 |
What is happening in the last step to cause the cost to jump from 5K to 7000k?
Usually I see the final cost be something (+/- a couple) to the last "Step",
the last FILTER or JOIN or SCAN or whatever. Is that extra cost, the
application of the filter to 1M rows from step 3? Why isn't that just shown on
step 2?
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