查询v$lock视图，仅仅53行数据hang住了40s
SQL> select * from v$version;
BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
PL/SQL Release 11.2.0.3.0 - Production
CORE 11.2.0.3.0 Production
TNS for Linux: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production
Elapsed: 00:00:00.00
SQL> select sid,addr from v$lock;
SID ADDR
---------- ----------------
767 00000001DA8FD150
393 00000001DA8FD5B0
958 00000001DA8FDAF0
385 00000001DA8FDDA8
....
....
1345 00000001DA8FECA0
385 00000001DA8FF3A0
53 rows selected.
Elapsed: 00:00:40.20
造成此种原因是sys的统计信息不准，导致走了错误的执行计划
SQL> select sid,addr from v$lock;
SID ADDR
---------- ----------------
194 00000001DA8FD850
5 00000001DA8FDA10
385 00000001DA8FE4A8
767 00000001DA8FD230
10 00000001DA8FF9D8
767 00000001DA8FD070
59 rows selected.
Elapsed: 00:00:26.42
Execution Plan
----------------------------------------------------------
Plan hash value: 1899724433
-------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 69 | 1 (100)| 00:00:01 |
|* 1 | HASH JOIN | | 1 | 69 | 1 (100)| 00:00:01 |
| 2 | MERGE JOIN CARTESIAN | | 100 | 5100 | 0 (0)| 00:00:01 |
|* 3 | FIXED TABLE FULL | X$KSUSE | 1 | 32 | 0 (0)| 00:00:01 |
| 4 | BUFFER SORT | | 100 | 1900 | 0 (0)| 00:00:01 |
| 5 | FIXED TABLE FULL | X$KSQRS | 100 | 1900 | 0 (0)| 00:00:01 |
| 6 | VIEW | GV$_LOCK | 10 | 180 | 0 (0)| 00:00:01 |
| 7 | UNION-ALL | | | | | |
|* 8 | FILTER | | | | | |
| 9 | VIEW | GV$_LOCK1 | 2 | 36 | 0 (0)| 00:00:01 |
| 10 | UNION-ALL | | | | | |
|* 11 | FIXED TABLE FULL| X$KDNSSF | 1 | 70 | 0 (0)| 00:00:01 |
|* 12 | FIXED TABLE FULL| X$KSQEQ | 1 | 70 | 0 (0)| 00:00:01 |
|* 13 | FIXED TABLE FULL | X$KTADM | 1 | 70 | 0 (0)| 00:00:01 |
|* 14 | FIXED TABLE FULL | X$KTATRFIL | 1 | 70 | 0 (0)| 00:00:01 |
|* 15 | FIXED TABLE FULL | X$KTATRFSL | 1 | 70 | 0 (0)| 00:00:01 |
|* 16 | FIXED TABLE FULL | X$KTATL | 1 | 70 | 0 (0)| 00:00:01 |
|* 17 | FIXED TABLE FULL | X$KTSTUSC | 1 | 70 | 0 (0)| 00:00:01 |
|* 18 | FIXED TABLE FULL | X$KTSTUSS | 1 | 70 | 0 (0)| 00:00:01 |
|* 19 | FIXED TABLE FULL | X$KTSTUSG | 1 | 70 | 0 (0)| 00:00:01 |
|* 20 | FIXED TABLE FULL | X$KTCXB | 1 | 70 | 0 (0)| 00:00:01 |
-------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - access("SADDR"="S"."ADDR" AND TO_CHAR(USERENV(‘INSTANCE‘))||RAWTOHEX("
RADDR")=TO_CHAR("R"."INST_ID")||RAWTOHEX("R"."ADDR"))
3 - filter("S"."INST_ID"=USERENV(‘INSTANCE‘))
8 - filter(USERENV(‘INSTANCE‘) IS NOT NULL)
11 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
12 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
13 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
14 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
15 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
16 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
17 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
18 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
19 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
20 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSPAFLG",1)<>0)
Statistics
----------------------------------------------------------
577 recursive calls
681 db block gets
0 consistent gets
49879 physical reads
0 redo size
2067 bytes sent via SQL*Net to client
553 bytes received via SQL*Net from client
5 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
59 rows processed
解决方案 1： 可以根据使用RBO进行查询
当给予规则的hint在查询中使用时，优化器将不考虑统计信息，并按照基于规则的优化器，更快地执行查询
SQL> select /*+rule+*/ sid,addr from v$lock;
SID ADDR
---------- ----------------
393 00000001DA8FD5B0
391 00000001DA8FF560
5 00000001DA8FDA10
203 00000001DA900D30
197 00000001DA8FE588
59 rows selected.
Elapsed: 00:00:00.04
Execution Plan
----------------------------------------------------------
Plan hash value: 2783647107
------------------------------------------------
| Id | Operation | Name |
------------------------------------------------
| 0 | SELECT STATEMENT | |
| 1 | MERGE JOIN | |
| 2 | SORT JOIN | |
| 3 | MERGE JOIN | |
| 4 | SORT JOIN | |
| 5 | FIXED TABLE FULL | X$KSQRS |
|* 6 | SORT JOIN | |
| 7 | VIEW | GV$_LOCK |
| 8 | UNION-ALL | |
|* 9 | FILTER | |
| 10 | VIEW | GV$_LOCK1 |
| 11 | UNION-ALL | |
|* 12 | FIXED TABLE FULL| X$KDNSSF |
|* 13 | FIXED TABLE FULL| X$KSQEQ |
|* 14 | FIXED TABLE FULL | X$KTADM |
|* 15 | FIXED TABLE FULL | X$KTATRFIL |
|* 16 | FIXED TABLE FULL | X$KTATRFSL |
|* 17 | FIXED TABLE FULL | X$KTATL |
|* 18 | FIXED TABLE FULL | X$KTSTUSC |
|* 19 | FIXED TABLE FULL | X$KTSTUSS |
|* 20 | FIXED TABLE FULL | X$KTSTUSG |
|* 21 | FIXED TABLE FULL | X$KTCXB |
|* 22 | SORT JOIN | |
|* 23 | FIXED TABLE FULL | X$KSUSE |
------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
6 - access(TO_CHAR(USERENV(‘INSTANCE‘))||RAWTOHEX("RADDR")=TO_CHAR("R
"."INST_ID")||RAWTOHEX("R"."ADDR"))
filter(TO_CHAR(USERENV(‘INSTANCE‘))||RAWTOHEX("RADDR")=TO_CHAR("R
"."INST_ID")||RAWTOHEX("R"."ADDR"))
9 - filter(USERENV(‘INSTANCE‘)=USERENV(‘INSTANCE‘))
12 - filter("INST_ID"=USERENV(‘INSTANCE‘) AND ("KSQLKMOD"<>0 OR
"KSQLKREQ"<>0) AND BITAND("KSSOBFLG",1)<>0)
13 - filter("INST_ID"=USERENV(‘INSTANCE‘) AND ("KSQLKMOD"<>0 OR
"KSQLKREQ"<>0) AND BITAND("KSSOBFLG",1)<>0)
14 - filter("INST_ID"=USERENV(‘INSTANCE‘) AND ("KSQLKMOD"<>0 OR
"KSQLKREQ"<>0) AND BITAND("KSSOBFLG",1)<>0)
15 - filter("INST_ID"=USERENV(‘INSTANCE‘) AND ("KSQLKMOD"<>0 OR
"KSQLKREQ"<>0) AND BITAND("KSSOBFLG",1)<>0)
16 - filter("INST_ID"=USERENV(‘INSTANCE‘) AND ("KSQLKMOD"<>0 OR
"KSQLKREQ"<>0) AND BITAND("KSSOBFLG",1)<>0)
17 - filter("INST_ID"=USERENV(‘INSTANCE‘) AND ("KSQLKMOD"<>0 OR
"KSQLKREQ"<>0) AND BITAND("KSSOBFLG",1)<>0)
18 - filter("INST_ID"=USERENV(‘INSTANCE‘) AND ("KSQLKMOD"<>0 OR
"KSQLKREQ"<>0) AND BITAND("KSSOBFLG",1)<>0)
19 - filter("INST_ID"=USERENV(‘INSTANCE‘) AND ("KSQLKMOD"<>0 OR
"KSQLKREQ"<>0) AND BITAND("KSSOBFLG",1)<>0)
20 - filter("INST_ID"=USERENV(‘INSTANCE‘) AND ("KSQLKMOD"<>0 OR
"KSQLKREQ"<>0) AND BITAND("KSSOBFLG",1)<>0)
21 - filter("INST_ID"=USERENV(‘INSTANCE‘) AND ("KSQLKMOD"<>0 OR
"KSQLKREQ"<>0) AND BITAND("KSSPAFLG",1)<>0)
22 - access("SADDR"="S"."ADDR")
filter("SADDR"="S"."ADDR")
23 - filter("S"."INST_ID"=USERENV(‘INSTANCE‘))
Note
-----
- rule based optimizer used (consider using cbo)
Statistics
----------------------------------------------------------
1 recursive calls
1 db block gets
0 consistent gets
0 physical reads
0 redo size
2138 bytes sent via SQL*Net to client
553 bytes received via SQL*Net from client
5 SQL*Net roundtrips to/from client
4 sorts (memory)
0 sorts (disk)
59 rows processed
解决方案2：
要***涉及本次查询数据字典的统计信息，结果还是依旧慢
SQL> exec dbms_stats.delete_schema_stats(‘sys‘);
PL/SQL procedure successfully completed.
Elapsed: 00:01:47.75
SQL> select sid,addr from v$lock
SID ADDR
---------- ----------------
194 00000001DA8FD850
5 00000001DA8FDA10
385 00000001DA8FE4A8
194 00000001DA8FE9E8
...............
10 00000001DA900378
767 00000001DA8FD070
60 rows selected.
Elapsed: 00:00:18.66
Execution Plan
----------------------------------------------------------
Plan hash value: 1899724433
-------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 69 | 1 (100)| 00:00:01 |
|* 1 | HASH JOIN | | 1 | 69 | 1 (100)| 00:00:01 |
| 2 | MERGE JOIN CARTESIAN | | 100 | 5100 | 0 (0)| 00:00:01 |
|* 3 | FIXED TABLE FULL | X$KSUSE | 1 | 32 | 0 (0)| 00:00:01 |
| 4 | BUFFER SORT | | 100 | 1900 | 0 (0)| 00:00:01 |
| 5 | FIXED TABLE FULL | X$KSQRS | 100 | 1900 | 0 (0)| 00:00:01 |
| 6 | VIEW | GV$_LOCK | 10 | 180 | 0 (0)| 00:00:01 |
| 7 | UNION-ALL | | | | | |
|* 8 | FILTER | | | | | |
| 9 | VIEW | GV$_LOCK1 | 2 | 36 | 0 (0)| 00:00:01 |
| 10 | UNION-ALL | | | | | |
|* 11 | FIXED TABLE FULL| X$KDNSSF | 1 | 70 | 0 (0)| 00:00:01 |
|* 12 | FIXED TABLE FULL| X$KSQEQ | 1 | 70 | 0 (0)| 00:00:01 |
|* 13 | FIXED TABLE FULL | X$KTADM | 1 | 70 | 0 (0)| 00:00:01 |
|* 14 | FIXED TABLE FULL | X$KTATRFIL | 1 | 70 | 0 (0)| 00:00:01 |
|* 15 | FIXED TABLE FULL | X$KTATRFSL | 1 | 70 | 0 (0)| 00:00:01 |
|* 16 | FIXED TABLE FULL | X$KTATL | 1 | 70 | 0 (0)| 00:00:01 |
|* 17 | FIXED TABLE FULL | X$KTSTUSC | 1 | 70 | 0 (0)| 00:00:01 |
|* 18 | FIXED TABLE FULL | X$KTSTUSS | 1 | 70 | 0 (0)| 00:00:01 |
|* 19 | FIXED TABLE FULL | X$KTSTUSG | 1 | 70 | 0 (0)| 00:00:01 |
|* 20 | FIXED TABLE FULL | X$KTCXB | 1 | 70 | 0 (0)| 00:00:01 |
-------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - access("SADDR"="S"."ADDR" AND TO_CHAR(USERENV(‘INSTANCE‘))||RAWTOHEX("
RADDR")=TO_CHAR("R"."INST_ID")||RAWTOHEX("R"."ADDR"))
3 - filter("S"."INST_ID"=USERENV(‘INSTANCE‘))
8 - filter(USERENV(‘INSTANCE‘) IS NOT NULL)
11 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
12 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
13 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
14 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
15 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
16 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
17 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
18 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
19 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSOBFLG",1)<>0)
20 - filter(("KSQLKMOD"<>0 OR "KSQLKREQ"<>0) AND
"INST_ID"=USERENV(‘INSTANCE‘) AND BITAND("KSSPAFLG",1)<>0)
Statistics
----------------------------------------------------------
577 recursive calls
1 db block gets
0 consistent gets
49879 physical reads
0 redo size
2081 bytes sent via SQL*Net to client
553 bytes received via SQL*Net from client
5 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
60 rows processed
只有重新收集统计信息
SQL> exec dbms_stats.gather_fixed_objects_stats
SQL> select sid,addr from v$lock;
SID ADDR
---------- ----------------
767 00000001DA8FD070
956 00000001DA8FCF90
767 00000001DA8FD150
385 00000001DA8FDCB0
767 00000001DA8FD690
...............
385 00000001DA8FDBD0
1339 00000001DA8FFAB8
971 00000001DA900E10
SID ADDR
---------- ----------------
971 00000001DA9001B8
56 rows selected.
Elapsed: 00:00:00.10
Execution Plan
----------------------------------------------------------
Plan hash value: 3524752130
--------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 4583 | 205K| 7 (100)| 00:00:01 |
| 1 | HASH JOIN | | 4583 | 205K| 7 (100)| 00:00:01 |
| 2 | HASH JOIN | | 66 | 2244 | 6 (100)| 00:00:01 |
| 3 | VIEW | GV$_LOCK | 66 | 1188 | 5 (100)| 00:00:01 |
| 4 | UNION-ALL | | | | | |
| 5 | FILTER | | | | | |
| 6 | VIEW | GV$_LOCK1 | 58 | 1044 | 3 (100)| 00:00:01 |
| 7 | UNION-ALL | | | | | |
| 8 | FIXED TABLE FULL| X$KDNSSF | 1 | 25 | 0 (0)| 00:00:01 |
| 9 | FIXED TABLE FULL| X$KSQEQ | 57 | 1482 | 3 (100)| 00:00:01 |
| 10 | FIXED TABLE FULL | X$KTADM | 1 | 25 | 1 (100)| 00:00:01 |
| 11 | FIXED TABLE FULL | X$KTATRFIL | 1 | 23 | 0 (0)| 00:00:01 |
| 12 | FIXED TABLE FULL | X$KTATRFSL | 1 | 23 | 0 (0)| 00:00:01 |
| 13 | FIXED TABLE FULL | X$KTATL | 1 | 33 | 0 (0)| 00:00:01 |
| 14 | FIXED TABLE FULL | X$KTSTUSC | 1 | 23 | 0 (0)| 00:00:01 |
| 15 | FIXED TABLE FULL | X$KTSTUSS | 1 | 25 | 0 (0)| 00:00:01 |
| 16 | FIXED TABLE FULL | X$KTSTUSG | 1 | 23 | 0 (0)| 00:00:01 |
| 17 | FIXED TABLE FULL | X$KTCXB | 1 | 25 | 0 (0)| 00:00:01 |
| 18 | FIXED TABLE FULL | X$KSUSE | 1528 | 24448 | 0 (0)| 00:00:01 |
| 19 | FIXED TABLE FULL | X$KSQRS | 6944 | 83328 | 1 (100)| 00:00:01 |
--------------------------------------------------------------------------------------
Statistics
----------------------------------------------------------
183 recursive calls
0 db block gets
405 consistent gets
0 physical reads
0 redo size
2125 bytes sent via SQL*Net to client
553 bytes received via SQL*Net from client
5 SQL*Net roundtrips to/from client
40 sorts (memory)
0 sorts (disk)
56 rows processed本文出自 “O Record” 博客，请务必保留此出处http://evils798.blog.51cto.com/8983296/1420900
查询v$lock视图慢到Hang住,布布扣,bubuko.com
原文地址：http://evils798.blog.51cto.com/8983296/1420900
