Hi,
> Even in Oracle, I don't believe rowid bypasses
> indexes, its more like an implicit SERIAL PRIMARY KEY field.
Well, I understand the point is not very relevant, since oid is not
similar to rowid. In Oracle, index scans are bypassed if we use rowid.
1)Access by unique index
SQL> select * from myt where id=200;
Execution Plan
----------------------------------------------------------
Plan hash value: 1325982734
--------------------------------------------------------------------------------
----
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
Time
|
--------------------------------------------------------------------------------
----
| 0 | SELECT STATEMENT | | 1 | 65 | 1 (0)|
00:00:
01 |
| 1 | TABLE ACCESS BY INDEX ROWID| MYT | 1 | 65 | 1 (0)|
00:00:
01 |
|* 2 | INDEX UNIQUE SCAN | MYDX | 1 | | 1 (0)|
00:00:
01 |
--------------------------------------------------------------------------------
2) Access by rowid
SQL> select * from myt where rowid='AAAH9iAAEAAAAafADH';
ID
----------
NAME
--------------------------------------------------------------------------------
200
REFCON$
Execution Plan
----------------------------------------------------------
Plan hash value: 4204525950
--------------------------------------------------------------------------------
---
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
Time
|
--------------------------------------------------------------------------------
---
| 0 | SELECT STATEMENT | | 1 | 77 | 1 (0)|
00:00:0
1 |
| 1 | TABLE ACCESS BY USER ROWID| MYT | 1 | 77 | 1 (0)|
00:00:0
Regards,
Jayadevan
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