I am making a proof of concept, and I am experimenting with strange behavior. I have a table broken down by range on a date field, and the cost of the request changes dramatically if I set a fixed date or one created by SYSDATE.
These are the explanatory plans:
SQL> SELECT *
2 FROM TP_TEST_ELEMENTO_TRAZABLE ET
3 WHERE ET.FEC_RECEPCION
4 BETWEEN TRUNC(SYSDATE-2) AND TRUNC(SYSDATE-1)
5 ;
5109 filas seleccionadas.
Plan de Ejecuci¾n
----------------------------------------------------------
Plan hash value: 1151442660
------------------------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop |
------------------------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 5008 | 85136 | 4504 (8)| 00:00:55 | | |
|* 1 | FILTER | | | | | | | |
| 2 | PARTITION RANGE ITERATOR| | 5008 | 85136 | 4504 (8)| 00:00:55 | KEY | KEY |
|* 3 | TABLE ACCESS FULL | TP_TEST_ELEMENTO_TRAZABLE | 5008 | 85136 | 4504 (8)| 00:00:55 | KEY | KEY |
------------------------------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter(TRUNC(SYSDATE@!-2)<=TRUNC(SYSDATE@!-1))
3 - filter("ET"."FEC_RECEPCION">=TRUNC(SYSDATE@!-2) AND "ET"."FEC_RECEPCION"<=TRUNC(SYSDATE@!-1))
EstadÝsticas
----------------------------------------------------------
1 recursive calls
0 db block gets
376 consistent gets
0 physical reads
0 redo size
137221 bytes sent via SQL*Net to client
4104 bytes received via SQL*Net from client
342 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
5109 rows processed
Using fixed dates:
SQL> SELECT *
2 FROM TP_TEST_ELEMENTO_TRAZABLE ET
3 WHERE ET.FEC_RECEPCION
4 BETWEEN TO_DATE('26/02/2017', 'DD/MM/YYYY') AND TO_DATE('27/02/2017', 'DD/MM/YYYY')
5 ;
5109 filas seleccionadas.
Plan de Ejecuci¾n
----------------------------------------------------------
Plan hash value: 3903280660
-----------------------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop |
-----------------------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 5008 | 85136 | 11 (0)| 00:00:01 | | |
| 1 | PARTITION RANGE ITERATOR| | 5008 | 85136 | 11 (0)| 00:00:01 | 607 | 608 |
|* 2 | TABLE ACCESS FULL | TP_TEST_ELEMENTO_TRAZABLE | 5008 | 85136 | 11 (0)| 00:00:01 | 607 | 608 |
-----------------------------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - filter("ET"."FEC_RECEPCION"<=TO_DATE(' 2017-02-27 00:00:00', 'syyyy-mm-dd hh24:mi:ss'))
EstadÝsticas
----------------------------------------------------------
1 recursive calls
0 db block gets
376 consistent gets
0 physical reads
0 redo size
137221 bytes sent via SQL*Net to client
4104 bytes received via SQL*Net from client
342 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
5109 rows processed
What is the difference that gives a value of 4504 and a value of 11?
Thanks in advance:)
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