查看oracle数据库表空间使用情况 非常慢！
2015-11-30 21:54
471 查看
1.现象
查看数据库表空间使用情况 非常慢！
2.诊断过程
2.1查看执行计划如下：
SQL> select * from table(dbms_xplan.display_cursor('0n0f0p6jm7tyf','','advanced'));
PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SQL_ID 0n0f0p6jm7tyf, child number 0
-------------------------------------
select a.tablespace_name, a.total_mb, b.free_mb,
to_char(100*b.free_mb/a.total_mb, '999.99') free_pct, b.free_exts,
b.max_mb, b.min_mb from (select tablespace_name,
to_char(sum(bytes)/1048576, '99999999.99') total_mb from
dba_data_files group by tablespace_name) a, (select tablespace_name,
to_char(sum(bytes)/1048576, '99999999.99') free_mb, count(*)
free_exts, to_char(max(bytes)/1048576, '999999') max_mb,
to_char(min(bytes)/1048576, '999999') min_mb from dba_free_space
group by tablespace_name) b where a.tablespace_name=b.tablespace_name(+)
order by free_pct
Execution Plan
----------------------------------------------------------
Plan hash value: 2720929131
------------------------------------------------------------------------------------------------------------------------
---------------------------------
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time
| TQ |IN-OUT| PQ Distrib |
------------------------------------------------------------------------------------------------------------------------
---------------------------------
| 0 | SELECT STATEMENT | | 17 | 1615 | | 1539 (2)| 00:00:
01 | | | |
| 1 | SORT ORDER BY | | 17 | 1615 | | 1539 (2)| 00:00:
01 | | | |
|* 2 | HASH JOIN OUTER | | 17 | 1615 | | 1538 (2)| 00:00:
。。。。
|* 22 | HASH JOIN | | 7377 | 785K| | 1010 (3)| 00:00:
01 | | | |
|* 23 | TABLE ACCESS FULL | TS$ | 12 | 312 | | 6 (0)| 00:00:
01 | | | |
|* 24 | HASH JOIN | | 7650 | 620K| 3344K| 1004 (3)| 00:00:
01 | | | |
|* 25 | TABLE ACCESS FULL | RECYCLEBIN$ | 142K| 1668K| | 579 (1)| 00:00:
01 | | | |
|* 26 | HASH JOIN | | 61538 | 4266K| | 20 (95)| 00:00:
01 | | | |
|* 27 | INDEX FULL SCAN | I_FILE2 | 30 | 180 | | 1 (0)| 00:00:
01 | | | |
| 28 | FIXED TABLE FULL | X$KTFBUE | 100K| 6347K| | 19 (100)| 00:00:
01 | | | |
| 29 | NESTED LOOPS | | 1 | 90 | | 495 (1)| 00:00:
01 | | | |
| 30 | NESTED LOOPS | | 28329 | 90 | | 495 (1)| 00:00:
01 | | | |
| 31 | NESTED LOOPS | | 1 | 78 | | 8 (0)| 00:00:
01 | | | |
| 32 | NESTED LOOPS | | 1 | 72 | | 8 (0)| 00:00:
01 | | | |
|* 33 | TABLE ACCESS FULL | TS$ | 1 | 20 | | 6 (0)| 00:00:
01 | | | |
| 34 | TABLE ACCESS CLUSTER | UET$ | 1 | 52 | | 2 (0)| 00:00:
01 | | | |
|* 35 | INDEX RANGE SCAN | I_FILE#_BLOCK# | 1 | | | 2 (0)| 00:00:
01 | | | |
|* 36 | INDEX UNIQUE SCAN | I_FILE2 | 1 | 6 | | 0 (0)| 00:00:
01 | | | |
|* 37 | INDEX RANGE SCAN | RECYCLEBIN$_TS | 28329 | | | 92 (0)| 00:00:
01 | | | |
|* 38 | TABLE ACCESS BY INDEX ROWID | RECYCLEBIN$ | 7ff7 1 | 12 | | 487 (1)| 00:00:
01 | | | |
| 39 | HASH GROUP BY | | 1 | 22 | | 1 (100)| 00:00:
01 | | | |
| 40 | PX COORDINATOR | | | | | |
| | | |
。。。
Statistics
----------------------------------------------------------
154755 recursive calls
1979 db block gets
797948 consistent gets
153583 physical reads
132 redo size
1919 bytes sent via SQL*Net to client
551 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
14 rows processed
2.2 查看回收站对象
SQL> select count(*) from dba_recyclebin;
COUNT(*)
----------
169423
3.解决办法
3.1清空回收站所有对象
SQL> purge dba_recyclebin;
3.2 重新收集统计信息
exec dbms_stats.gather_table_stats(ownname => 'SYS',tabname => 'RECYCLEBIN$', estimate_percent => 100, method_opt=> 'for all indexed columns',degree=>8);
4.解决后执行计划
Execution Plan
----------------------------------------------------------
Plan hash value: 1258632344
------------------------------------------------------------------------------------------------------------------------
-------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
TQ |IN-OUT| PQ Distrib |
------------------------------------------------------------------------------------------------------------------------
-------------------------
| 0 | SELECT STATEMENT | | 17 | 1615 | 56 (13)| 00:00:01 |
| | |
。。。。
|* 21 | INDEX UNIQUE SCAN | I_FILE2 | 1 | 6 | 0 (0)| 00:00:01 |
| | |
| 22 | NESTED LOOPS | | 1 | 109 | 12 (17)| 00:00:01 |
| | |
| 23 | NESTED LOOPS | | 1 | 103 | 12 (17)| 00:00:01 |
| | |
| 24 | MERGE JOIN | | 1 | 38 | 11 (10)| 00:00:01 |
| | |
|* 25 | TABLE ACCESS BY INDEX ROWID | RECYCLEBIN$ | 1 | 12 | 4 (0)| 00:00:01 |
| | |
| 26 | INDEX FULL SCAN | RECYCLEBIN$_TS | 1 | | 3 (0)| 00:00:01 |
| | |
|* 27 | SORT JOIN | | 12 | 312 | 7 (15)| 00:00:01 |
| | |
|* 28 | TABLE ACCESS FULL | TS$ | 12 | 312 | 6 (0)| 00:00:01 |
| | |
|* 29 | FIXED TABLE FIXED INDEX | X$KTFBUE (ind:1) | 1 | 65 | 1 (100)| 00:00:01 |
| | |
|* 30 | INDEX UNIQUE SCAN | I_FILE2 | 1 | 6 | 0 (0)| 00:00:01 |
| | |
| 31 | NESTED LOOPS | | 1 | 90 | 10 (0)| 00:00:01 |
| | |
| 32 | NESTED LOOPS | | 1 | 90 | 10 (0)| 00:00:01 |
| | |
| 33 | NESTED LOOPS | | 1 | 78 | 8 (0)| 00:00:01 |
| | |
| 34 | NESTED LOOPS | | 1 | 72 | 8 (0)| 00:00:01 |
| | |
|* 35 | TABLE ACCESS FULL | TS$ | 1 | 20 | 6 (0)| 00:00:01 |
| | |
| 36 | TABLE ACCESS CLUSTER | UET$ | 1 | 52 | 2 (0)| 00:00:01 |
| | |
|* 37 | INDEX RANGE SCAN | I_FILE#_BLOCK# | 1 | | 2 (0)| 00:00:01 |
| | |
|* 38 | INDEX UNIQUE SCAN | I_FILE2 | 1 | 6 | 0 (0)| 00:00:01 |
| | |
|* 39 | INDEX RANGE SCAN | RECYCLEBIN$_TS | 1 | | 2 (0)| 00:00:01 |
| | |
|* 40 | TABLE ACCESS BY INDEX ROWID | RECYCLEBIN$ | 1 | 12 | 2 (0)| 00:00:01 |
| | |
| 41 | HASH GROUP BY | | 1 | 22 | 1 (100)| 00:00:01 |
| | |
。。。。
Statistics
----------------------------------------------------------
48 recursive calls
589 db block gets
806 consistent gets
1 physical reads
0 redo size
1909 bytes sent via SQL*Net to client
552 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
2 sorts (memory)
0 sorts (disk)
14 rows processed
5.原因
应用测试，大量删除对象，导致回收站对象过多。
==补充：
又一次发现查看表空间使用率慢！ 查看plan 发现查询dba_free_space时比较慢：
VIEW | DBA_FREE_SPACE | 14599 | 313K| 75 (26)| 00:00:01
select count(*) from dba_free_space;--耗时76s
purge dba_recyclebin;后执行<1s
查看数据库表空间使用情况 非常慢！
2.诊断过程
2.1查看执行计划如下：
SQL> select * from table(dbms_xplan.display_cursor('0n0f0p6jm7tyf','','advanced'));
PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SQL_ID 0n0f0p6jm7tyf, child number 0
-------------------------------------
select a.tablespace_name, a.total_mb, b.free_mb,
to_char(100*b.free_mb/a.total_mb, '999.99') free_pct, b.free_exts,
b.max_mb, b.min_mb from (select tablespace_name,
to_char(sum(bytes)/1048576, '99999999.99') total_mb from
dba_data_files group by tablespace_name) a, (select tablespace_name,
to_char(sum(bytes)/1048576, '99999999.99') free_mb, count(*)
free_exts, to_char(max(bytes)/1048576, '999999') max_mb,
to_char(min(bytes)/1048576, '999999') min_mb from dba_free_space
group by tablespace_name) b where a.tablespace_name=b.tablespace_name(+)
order by free_pct
Execution Plan
----------------------------------------------------------
Plan hash value: 2720929131
------------------------------------------------------------------------------------------------------------------------
---------------------------------
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time
| TQ |IN-OUT| PQ Distrib |
------------------------------------------------------------------------------------------------------------------------
---------------------------------
| 0 | SELECT STATEMENT | | 17 | 1615 | | 1539 (2)| 00:00:
01 | | | |
| 1 | SORT ORDER BY | | 17 | 1615 | | 1539 (2)| 00:00:
01 | | | |
|* 2 | HASH JOIN OUTER | | 17 | 1615 | | 1538 (2)| 00:00:
。。。。
|* 22 | HASH JOIN | | 7377 | 785K| | 1010 (3)| 00:00:
01 | | | |
|* 23 | TABLE ACCESS FULL | TS$ | 12 | 312 | | 6 (0)| 00:00:
01 | | | |
|* 24 | HASH JOIN | | 7650 | 620K| 3344K| 1004 (3)| 00:00:
01 | | | |
|* 25 | TABLE ACCESS FULL | RECYCLEBIN$ | 142K| 1668K| | 579 (1)| 00:00:
01 | | | |
|* 26 | HASH JOIN | | 61538 | 4266K| | 20 (95)| 00:00:
01 | | | |
|* 27 | INDEX FULL SCAN | I_FILE2 | 30 | 180 | | 1 (0)| 00:00:
01 | | | |
| 28 | FIXED TABLE FULL | X$KTFBUE | 100K| 6347K| | 19 (100)| 00:00:
01 | | | |
| 29 | NESTED LOOPS | | 1 | 90 | | 495 (1)| 00:00:
01 | | | |
| 30 | NESTED LOOPS | | 28329 | 90 | | 495 (1)| 00:00:
01 | | | |
| 31 | NESTED LOOPS | | 1 | 78 | | 8 (0)| 00:00:
01 | | | |
| 32 | NESTED LOOPS | | 1 | 72 | | 8 (0)| 00:00:
01 | | | |
|* 33 | TABLE ACCESS FULL | TS$ | 1 | 20 | | 6 (0)| 00:00:
01 | | | |
| 34 | TABLE ACCESS CLUSTER | UET$ | 1 | 52 | | 2 (0)| 00:00:
01 | | | |
|* 35 | INDEX RANGE SCAN | I_FILE#_BLOCK# | 1 | | | 2 (0)| 00:00:
01 | | | |
|* 36 | INDEX UNIQUE SCAN | I_FILE2 | 1 | 6 | | 0 (0)| 00:00:
01 | | | |
|* 37 | INDEX RANGE SCAN | RECYCLEBIN$_TS | 28329 | | | 92 (0)| 00:00:
01 | | | |
|* 38 | TABLE ACCESS BY INDEX ROWID | RECYCLEBIN$ | 7ff7 1 | 12 | | 487 (1)| 00:00:
01 | | | |
| 39 | HASH GROUP BY | | 1 | 22 | | 1 (100)| 00:00:
01 | | | |
| 40 | PX COORDINATOR | | | | | |
| | | |
。。。
Statistics
----------------------------------------------------------
154755 recursive calls
1979 db block gets
797948 consistent gets
153583 physical reads
132 redo size
1919 bytes sent via SQL*Net to client
551 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
14 rows processed
2.2 查看回收站对象
SQL> select count(*) from dba_recyclebin;
COUNT(*)
----------
169423
3.解决办法
3.1清空回收站所有对象
SQL> purge dba_recyclebin;
3.2 重新收集统计信息
exec dbms_stats.gather_table_stats(ownname => 'SYS',tabname => 'RECYCLEBIN$', estimate_percent => 100, method_opt=> 'for all indexed columns',degree=>8);
4.解决后执行计划
Execution Plan
----------------------------------------------------------
Plan hash value: 1258632344
------------------------------------------------------------------------------------------------------------------------
-------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
TQ |IN-OUT| PQ Distrib |
------------------------------------------------------------------------------------------------------------------------
-------------------------
| 0 | SELECT STATEMENT | | 17 | 1615 | 56 (13)| 00:00:01 |
| | |
。。。。
|* 21 | INDEX UNIQUE SCAN | I_FILE2 | 1 | 6 | 0 (0)| 00:00:01 |
| | |
| 22 | NESTED LOOPS | | 1 | 109 | 12 (17)| 00:00:01 |
| | |
| 23 | NESTED LOOPS | | 1 | 103 | 12 (17)| 00:00:01 |
| | |
| 24 | MERGE JOIN | | 1 | 38 | 11 (10)| 00:00:01 |
| | |
|* 25 | TABLE ACCESS BY INDEX ROWID | RECYCLEBIN$ | 1 | 12 | 4 (0)| 00:00:01 |
| | |
| 26 | INDEX FULL SCAN | RECYCLEBIN$_TS | 1 | | 3 (0)| 00:00:01 |
| | |
|* 27 | SORT JOIN | | 12 | 312 | 7 (15)| 00:00:01 |
| | |
|* 28 | TABLE ACCESS FULL | TS$ | 12 | 312 | 6 (0)| 00:00:01 |
| | |
|* 29 | FIXED TABLE FIXED INDEX | X$KTFBUE (ind:1) | 1 | 65 | 1 (100)| 00:00:01 |
| | |
|* 30 | INDEX UNIQUE SCAN | I_FILE2 | 1 | 6 | 0 (0)| 00:00:01 |
| | |
| 31 | NESTED LOOPS | | 1 | 90 | 10 (0)| 00:00:01 |
| | |
| 32 | NESTED LOOPS | | 1 | 90 | 10 (0)| 00:00:01 |
| | |
| 33 | NESTED LOOPS | | 1 | 78 | 8 (0)| 00:00:01 |
| | |
| 34 | NESTED LOOPS | | 1 | 72 | 8 (0)| 00:00:01 |
| | |
|* 35 | TABLE ACCESS FULL | TS$ | 1 | 20 | 6 (0)| 00:00:01 |
| | |
| 36 | TABLE ACCESS CLUSTER | UET$ | 1 | 52 | 2 (0)| 00:00:01 |
| | |
|* 37 | INDEX RANGE SCAN | I_FILE#_BLOCK# | 1 | | 2 (0)| 00:00:01 |
| | |
|* 38 | INDEX UNIQUE SCAN | I_FILE2 | 1 | 6 | 0 (0)| 00:00:01 |
| | |
|* 39 | INDEX RANGE SCAN | RECYCLEBIN$_TS | 1 | | 2 (0)| 00:00:01 |
| | |
|* 40 | TABLE ACCESS BY INDEX ROWID | RECYCLEBIN$ | 1 | 12 | 2 (0)| 00:00:01 |
| | |
| 41 | HASH GROUP BY | | 1 | 22 | 1 (100)| 00:00:01 |
| | |
。。。。
Statistics
----------------------------------------------------------
48 recursive calls
589 db block gets
806 consistent gets
1 physical reads
0 redo size
1909 bytes sent via SQL*Net to client
552 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
2 sorts (memory)
0 sorts (disk)
14 rows processed
5.原因
应用测试，大量删除对象，导致回收站对象过多。
==补充：
又一次发现查看表空间使用率慢！ 查看plan 发现查询dba_free_space时比较慢：
VIEW | DBA_FREE_SPACE | 14599 | 313K| 75 (26)| 00:00:01
select count(*) from dba_free_space;--耗时76s
purge dba_recyclebin;后执行<1s
来自 “ ITPUB博客 ” ，链接：http://blog.itpub.net/27126919/viewspace-1850055/，如需转载，请注明出处，否则将追究法律责任。
转载于:http://blog.itpub.net/27126919/viewspace-1850055/
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