測試oracle插入 刪除 更新表的日誌開銷

###############測試插入 刪除 更新表的日誌開銷
建立表
SYS@orcl >create table ssr(id int);
查詢表空間，sys默認system,插入數據後此分配空間
SYS@orcl >select tablespace_name, segment_name from user_segments where segment_name='SSR';
TABLESPACE_NAME            SEGMENT_NAME
---------------------------------------------------------
SYSTEM                   SSR



建立空表
GUOYF@orcl 09:20:01>create table aa as select * from all_objects where 1=0;
查詢現有日誌大小
select a.name,b.value from v$statname a join v$mystat b on a.statistic#=b.statistic# where a.name='redo size';

NAME                                      VALUE
---------------------------------------------------------------- ----------

redo size                                 254388

插入數據
GUOYF@orcl 09:24:01>insert into aa select * from all_objects where rownum<100;
查詢日誌大小


select a.name,b.value from v$statname a join v$mystat b on a.statistic#=b.statistic# where a.name='redo size';

NAME                                      VALUE
---------------------------------------------------------------- ----------
redo size                                 268768



更新數據
GUOYF@orcl 09:27:47>update aa set owner='guoyf' where owner='SYS';


查看日誌大小
select a.name,b.value from v$statname a join v$mystat b on a.statistic#=b.statistic# where a.name='redo size';

NAME                                      VALUE
---------------------------------------------------------------- ----------
redo size                                294612
刪除數據
GUOYF@orcl 09:29:10>delete from aa where owner='guoyf';
查看日誌大小
select a.name,b.value from v$statname a join v$mystat b on a.statistic#=b.statistic# where a.name='redo size';

NAME                                      VALUE
---------------------------------------------------------------- ----------
redo size                                 330832

經過以上數據代表產生日誌量
刪除》更新》插入


    
AUTOTRACE是一個SQL*Plus工具,用於跟蹤SQL的執行計劃,收集執行時所耗用資源的統計信息
        set autotrace off :缺省值，將不生成autotrace 報告

        set autotrace on :包含執行計劃和統計信息

        set autotrace traceonly :等同於set autotrace on，但不顯示查詢輸出的結果

        set autotrace on explain :只顯示優化器執行路徑報告

        set autotrace on statistics :只顯示執行統計信息


#######測試delete沒法釋放表空間
建立表
SQL> create table bb as select * from dba_objects;
開啓啊autotrace
SQL> set autotrace on ;
##查看I/O
SQL> select count(*) from bb;

 COUNT(*)
----------
     72573


Execution Plan
----------------------------------------------------------
Plan hash value: 162157452

-------------------------------------------------------------------
| Id  | Operation       | Name | Rows  | Cost (%CPU)| Time      |
-------------------------------------------------------------------
|   0 | SELECT STATEMENT   |      |    1 |   290   (1)| 00:00:04 |
|   1 |  SORT AGGREGATE    |      |    1 |           |      |
|   2 |   TABLE ACCESS FULL| BB   | 69590 |   290   (1)| 00:00:04 |
-------------------------------------------------------------------

Note
-----
   - dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
     28  recursive calls
      0  db block gets
       1106  consistent gets
       1034  physical reads
      0  redo size
    528  bytes sent via SQL*Net to client
    523  bytes received via SQL*Net from client
      2  SQL*Net roundtrips to/from client
      0  sorts (memory)
      0  sorts (disk)
      1  rows processed


關閉啊autotrace
SQL> set autotrace off;
刪除表
SQL> delete from bb;

72653 rows deleted.

SQL> select count(*) from bb;

  COUNT(*)
----------
     0

SQL> commit;

Commit complete.

SQL> set autotrace on;
SQL> select count(*) from bb;

  COUNT(*)
----------
     0


Execution Plan
----------------------------------------------------------
Plan hash value: 162157452

-------------------------------------------------------------------
| Id  | Operation       | Name | Rows  | Cost (%CPU)| Time      |
-------------------------------------------------------------------
|   0 | SELECT STATEMENT   |      |    1 |   289   (0)| 00:00:04 |
|   1 |  SORT AGGREGATE    |      |    1 |           |      |
|   2 |   TABLE ACCESS FULL| BB   |    1 |   289   (0)| 00:00:04 |
-------------------------------------------------------------------

Note
-----
   - dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
      0  recursive calls
      0  db block gets
       1039  consistent gets
      0  physical reads
      0  redo size
    525  bytes sent via SQL*Net to client
    523  bytes received via SQL*Net from client
      2  SQL*Net roundtrips to/from client
      0  sorts (memory)
      0  sorts (disk)
      1  rows processed


SQL> truncate table bb;

Table truncated.

SQL> select count(*) from bb;

   COUNT(*)
----------
     0


Execution Plan
----------------------------------------------------------
Plan hash value: 162157452

-------------------------------------------------------------------
| Id  | Operation       | Name | Rows  | Cost (%CPU)| Time      |
-------------------------------------------------------------------
|   0 | SELECT STATEMENT   |      |    1 |    2   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE    |      |    1 |           |      |
|   2 |   TABLE ACCESS FULL| BB   |    1 |    2   (0)| 00:00:01 |
-------------------------------------------------------------------

Note
-----
   - dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
     20  recursive calls
      1  db block gets
     10  consistent gets
      0  physical reads
     96  redo size
    525  bytes sent via SQL*Net to client
    523  bytes received via SQL*Net from client
      2  SQL*Net roundtrips to/from client
      0  sorts (memory)
      0  sorts (disk)
      1  rows processed