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|
SQL> connect wissem
Enter password:
Connected.
SQL>
SQL> CREATE TABLE test_part_perf (
id NUMBER,
created_month VARCHAR2(10),
description VARCHAR2(50),
created_date DATE
)
PARTITION BY LIST (created_month)
(
PARTITION part_aa values ('201101'),
partition part_bb values ('201102'),
partition part_cc values (NULL)
)
TABLESPACE EXAMPLE; 2 3 4 5 6 7 8 9 10 11 12 13
Table created.
SQL>
SQL> BEGIN
for i in 1..10000 loop
insert into test_part_perf values (i, '201101',NULL,to_date('20110101','YYYYMMDD'));
end loop;
commit;
end; 2 3 4 5 6
7 /
PL/SQL procedure successfully completed.
SQL> BEGIN
for i in 1..5000 loop
insert into test_part_perf values (i, '201102',NULL,to_date('20110201','YYYYMMDD'));
end loop;
commit;
end; 2 3 4 5 6
7 /
PL/SQL procedure successfully completed.
SQL> BEGIN
for i in 1..20000 loop
insert into test_part_perf values (i, NULL,NULL,to_date('20110101','YYYYMMDD'));
end loop;
commit;
end; 2 3 4 5 6
7 /
PL/SQL procedure successfully completed.
SQL>
SQL> Explain plan for
select count(*)
from test_part_perf
where created_month= '201101'; 2 3 4
Explained.
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 1186165449
--------------------------------------------------------------------------------
-------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| T
ime | Pstart| Pstop |
--------------------------------------------------------------------------------
-------------------------
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 7 | 11 (0)| 0
0:00:01 | | |
| 1 | SORT AGGREGATE | | 1 | 7 | |
| | |
| 2 | PARTITION LIST SINGLE| | 10000 | 70000 | 11 (0)| 0
0:00:01 | 1 | 1 |
| 3 | TABLE ACCESS FULL | TEST_PART_PERF | 10000 | 70000 | 11 (0)| 0
0:00:01 | 1 | 1 |
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
-------------------------
Note
-----
- dynamic sampling used for this statement (level=2)
14 rows selected.
SQL>
SQL> --- utiliser
Explain plan for
select count(*)
from test_part_perf
where created_month is null;SQL> 2 3 4
Explained.
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 1186165449
--------------------------------------------------------------------------------
-------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| T
ime | Pstart| Pstop |
--------------------------------------------------------------------------------
-------------------------
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 7 | 17 (0)| 0
0:00:01 | | |
| 1 | SORT AGGREGATE | | 1 | 7 | |
| | |
| 2 | PARTITION LIST SINGLE| | 20000 | 136K| 17 (0)| 0
0:00:01 | 3 | 3 |
| 3 | TABLE ACCESS FULL | TEST_PART_PERF | 20000 | 136K| 17 (0)| 0
0:00:01 | 3 | 3 |
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
-------------------------
Note
-----
- dynamic sampling used for this statement (level=2)
14 rows selected.
SQL>
SQL> alter table test_part_perf add partition part_dd values ('000000');
Table altered.
SQL>
SQL> alter table test_part_perf enable row movement;
Table altered.
SQL> update test_part_perf set created_month='000000' where created_month is null;
20000 rows updated.
SQL> commit;
Commit complete.
SQL>
SQL> Explain plan for
select count(*)
from test_part_perf
where created_month = '000000'; 2 3 4
Explained.
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 1186165449
--------------------------------------------------------------------------------
-------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| T
ime | Pstart| Pstop |
--------------------------------------------------------------------------------
-------------------------
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 7 | 22 (0)| 0
0:00:01 | | |
| 1 | SORT AGGREGATE | | 1 | 7 | |
| | |
| 2 | PARTITION LIST SINGLE| | 20450 | 139K| 22 (0)| 0
0:00:01 | KEY | KEY |
| 3 | TABLE ACCESS FULL | TEST_PART_PERF | 20450 | 139K| 22 (0)| 0
0:00:01 | 4 | 4 |
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
-------------------------
Note
-----
- dynamic sampling used for this statement (level=2)
14 rows selected.
SQL>
SQL> select count(*)
from test_part_perf
where created_month = '000000';
COUNT(*)
----------
20000
SQL> |
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