OFFSET – FETCH Versus ROWNUM In Oracle

Lukas Eder compares the OFFSET FETCH logic versus using ROWNUM for grabbing an ordered sub-selection of rows in Oracle:

Now, while the SQL transformation from FETCH FIRST to ROW_NUMBER() filtering is certainly correct, the execution plan doesn’t really make me happy. Consider the ROWNUM based query:

---------------------------------------------------------
| Id  | Operation                     | Name    | Rows  |
---------------------------------------------------------
|   0 | SELECT STATEMENT              |         |       |
|*  1 |  COUNT STOPKEY                |         |       |
|   2 |   VIEW                        |         |     1 |
|   3 |    TABLE ACCESS BY INDEX ROWID| FILM    |  1000 |
|   4 |     INDEX FULL SCAN           | PK_FILM |     1 |
---------------------------------------------------------
 
Predicate Information (identified by operation id):
---------------------------------------------------
 
   1 - filter(ROWNUM=1)

And compare that to the FETCH FIRST query:

-------------------------------------------------
| Id  | Operation                | Name | Rows  |
-------------------------------------------------
|   0 | SELECT STATEMENT         |      |       |
|*  1 |  VIEW                    |      |     1 |
|*  2 |   WINDOW SORT PUSHED RANK|      |  1000 |
|   3 |    TABLE ACCESS FULL     | FILM |  1000 |
-------------------------------------------------
 
Predicate Information (identified by operation id):
---------------------------------------------------
 
   1 - filter("from$_subquery$_002"."rowlimit_$$_rownumber"<=1)
   2 - filter(ROW_NUMBER() OVER ( ORDER BY "FILM"."FILM_ID")<=1)

Lukas digs into this and is not the biggest fan of OFFSET-FETCH.  On the SQL Server side, my anecdotal experience has been that it doesn’t perform nearly as well as you’d like either.