執行計劃出現BITMAP CONVERSION TO ROWIDS的解釋!

BITMAP CONVERSION TO ROWIDS

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| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
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| 0 | SELECT STATEMENT | | 16 | 944 | 139 (3)| 00:00:02 |
| 1 | SORT GROUP BY | | 16 | 944 | 139 (3)| 00:00:02 |
| 2 | NESTED LOOPS | | 16 | 944 | 138 (2)| 00:00:02 |
| 3 | NESTED LOOPS | | 16 | 528 | 135 (3)| 00:00:02 |
| 4 | TABLE ACCESS BY INDEX ROWID | TBL_MERCHANT_ITEMS | 14 | 140 | 1 (0)| 00:00:01 |
|* 5 | INDEX RANGE SCAN | IDX_TBL_MERCHANT_ITEMS | 14 | | 1 (0)| 00:00:01 |
|* 6 | TABLE ACCESS BY INDEX ROWID | TBL_INVENTORY_TRACKED_ITEMS | 1 | 23 | 135 (3)| 00:00:02 |
| 7 | BITMAP CONVERSION TO ROWIDS | | | | | |
| 8 | BITMAP AND | | | | | |
| 9 | BITMAP CONVERSION FROM ROWIDS| | | | | |
| 10 | SORT ORDER BY | | | | | |
|* 11 | INDEX RANGE SCAN | IDX_ITI_ITEM_STATUS | 698 | | 1 (0)| 00:00:01 |
| 12 | BITMAP CONVERSION FROM ROWIDS| | | | | |
| 13 | SORT ORDER BY | | | | | |
|* 14 | INDEX RANGE SCAN | IDX_TITI_SERNUM | 698 | | 6 (0)| 00:00:01 |
| 15 | TABLE ACCESS BY INDEX ROWID | TBL_CLIENTS | 1 | 26 | 1 (0)| 00:00:01 |
|* 16 | INDEX UNIQUE SCAN | IDX_TC_CLINUM | 1 | | 1 (0)| 00:00:01 |
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alter session set "_b_tree_bitmap_plans"=false;

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