查询 v$lock 很慢，hint来帮忙-凯发app官方网站

凯发app官方网站-凯发k8官网下载客户端中心 | | 凯发app官方网站-凯发k8官网下载客户端中心

沧海拾贝

凯发app官方网站首页　| 　博文目录　| 　关于我

brjl

  • 博客访问： 3502679
  • 博文数量： 718
  • 博客积分： 1860
  • 博客等级： 上尉
  • 技术积分： 7790
  • 用 户 组： 普通用户
  • 注册时间： 2008-04-07 08:51
个人简介

偶尔有空上来看看

文章分类

全部博文（718）

文章存档

2024年（4）

2023年（74）

2022年（134）

2021年（238）

2020年（115）

2019年（11）

2018年（9）

2017年（9）

2016年（17）

2015年（7）

2014年（4）

2013年（1）

2012年（11）

2011年（27）

2010年（35）

2009年（11）

2008年（11）

我的朋友
最近访客
推荐博文
相关博文
  • ·
  • ·
  • ·
  • ·
  • ·
  • ·
  • ·
  • ·
  • ·
  • ·
查询 v$lock 很慢，hint来帮忙

分类： oracle

2021-05-18 13:56:01


看一眼数据库负载 11.2.0.4 rac，居然是监控系统占用资源最多，首当其冲的就是以下语句

select count(*) from v$lock where type = 'tx' and request = 6;
很简单，检查当前有几个请求独占的锁


查询时间很长，其中出现了之前提到过的“合并连接卡迪森”

看看访问路径，过滤条件
  1. sql_id b1na79hpa7k3p, child number 0
  2. -------------------------------------
  3. select count(*) from v$lock where type = 'tx' and request = 6;

  5. plan hash value: 2384831130

  7. ---------------------------------------------------------------------------
  8. | id | operation | name | rows | bytes | cost (%cpu)|
  9. ---------------------------------------------------------------------------
  10. | 0 | select statement | | | | 1 (100)|
  11. | 1 | sort aggregate | | 1 | 53 | |
  12. |* 2 | hash join | | 1 | 53 | 0 (0)|
  13. | 3 | merge join cartesian | | 1 | 41 | 0 (0)|
  14. |* 4 | fixed table full | x$ksuse | 1 | 19 | 0 (0)|
  15. | 5 | buffer sort | | 1 | 22 | 0 (0)|
  16. |* 6 | fixed table full | x$ksqrs | 1 | 22 | 0 (0)|
  17. | 7 | view | gv$_lock | 10 | 120 | 0 (0)|
  18. | 8 | union-all | | | | |
  19. |* 9 | filter | | | | |
  20. | 10 | view | gv$_lock1 | 2 | 24 | 0 (0)|
  21. | 11 | union-all | | | | |
  22. |* 12 | fixed table full| x$kdnssf | 1 | 64 | 0 (0)|
  23. |* 13 | fixed table full| x$ksqeq | 1 | 64 | 0 (0)|
  24. |* 14 | fixed table full | x$ktadm | 1 | 64 | 0 (0)|
  25. |* 15 | fixed table full | x$ktatrfil | 1 | 64 | 0 (0)|
  26. |* 16 | fixed table full | x$ktatrfsl | 1 | 64 | 0 (0)|
  27. |* 17 | fixed table full | x$ktatl | 1 | 64 | 0 (0)|
  28. |* 18 | fixed table full | x$ktstusc | 1 | 64 | 0 (0)|
  29. |* 19 | fixed table full | x$ktstuss | 1 | 64 | 0 (0)|
  30. |* 20 | fixed table full | x$ktstusg | 1 | 64 | 0 (0)|
  31. |* 21 | fixed table full | x$ktcxb | 1 | 64 | 0 (0)|
  32. ---------------------------------------------------------------------------

  34. query block name / object alias (identified by operation id):
  35. -------------------------------------------------------------

  37.    1 - sel$af73c875
  38.    4 - sel$af73c875 / s@sel$4
  39.    6 - sel$af73c875 / r@sel$4
  40.    7 - set$1 / gv$_lock@sel$5
  41.    8 - set$1
  42.    9 - sel$68b588a0
  43.   10 - set$2 / gv$_lock1@sel$7
  44.   11 - set$2
  45.   12 - sel$8 / x$kdnssf@sel$8
  46.   13 - sel$9 / x$ksqeq@sel$9
  47.   14 - sel$10 / x$ktadm@sel$10
  48.   15 - sel$11 / x$ktatrfil@sel$11
  49.   16 - sel$12 / x$ktatrfsl@sel$12
  50.   17 - sel$13 / x$ktatl@sel$13
  51.   18 - sel$14 / x$ktstusc@sel$14
  52.   19 - sel$15 / x$ktstuss@sel$15
  53.   20 - sel$16 / x$ktstusg@sel$16
  54.   21 - sel$17 / x$ktcxb@sel$17

  56. outline data
  57. -------------

  59.   /*
  60.       begin_outline_data
  61.       ignore_optim_embedded_hints
  62.       optimizer_features_enable('11.2.0.4')
  63.       db_version('11.2.0.4')
  64.       opt_param('_optim_peek_user_binds' 'false')
  65.       opt_param('_optimizer_extended_cursor_sharing' 'none')
  66.       opt_param('_gby_hash_aggregation_enabled' 'false')
  67.       opt_param('_optimizer_extended_cursor_sharing_rel' 'none')
  68.       opt_param('_optimizer_adaptive_cursor_sharing' 'false')
  69.       opt_param('_optimizer_use_feedback' 'false')
  70.       all_rows
  71.       outline_leaf(@"sel$8")
  72.       outline_leaf(@"sel$9")
  73.       outline_leaf(@"set$2")
  74.       outline_leaf(@"sel$68b588a0")
  75.       merge(@"sel$7")
  76.       outline_leaf(@"sel$10")
  77.       outline_leaf(@"sel$11")
  78.       outline_leaf(@"sel$12")
  79.       outline_leaf(@"sel$13")
  80.       outline_leaf(@"sel$14")
  81.       outline_leaf(@"sel$15")
  82.       outline_leaf(@"sel$16")
  83.       outline_leaf(@"sel$17")
  84.       outline_leaf(@"set$1")
  85.       outline_leaf(@"sel$af73c875")
  86.       merge(@"sel$71d7a081")
  87.       outline(@"sel$6")
  88.       outline(@"sel$7")
  89.       outline(@"sel$1")
  90.       outline(@"sel$71d7a081")
  91.       merge(@"sel$c8360722")
  92.       outline(@"sel$2")
  93.       outline(@"sel$c8360722")
  94.       merge(@"sel$7286615e")
  95.       outline(@"sel$3")
  96.       outline(@"sel$7286615e")
  97.       merge(@"sel$5")
  98.       outline(@"sel$4")
  99.       outline(@"sel$5")
  100.       full(@"sel$af73c875" "s"@"sel$4")
  101.       full(@"sel$af73c875" "r"@"sel$4")
  102.       no_access(@"sel$af73c875" "gv$_lock"@"sel$5")
  103.       leading(@"sel$af73c875" "s"@"sel$4" "r"@"sel$4" "gv$_lock"@"sel$5")
  104.       use_merge_cartesian(@"sel$af73c875" "r"@"sel$4")
  105.       use_hash(@"sel$af73c875" "gv$_lock"@"sel$5")
  106.       full(@"sel$17" "x$ktcxb"@"sel$17")
  107.       full(@"sel$16" "x$ktstusg"@"sel$16")
  108.       full(@"sel$15" "x$ktstuss"@"sel$15")
  109.       full(@"sel$14" "x$ktstusc"@"sel$14")
  110.       full(@"sel$13" "x$ktatl"@"sel$13")
  111.       full(@"sel$12" "x$ktatrfsl"@"sel$12")
  112.       full(@"sel$11" "x$ktatrfil"@"sel$11")
  113.       full(@"sel$10" "x$ktadm"@"sel$10")
  114.       no_access(@"sel$68b588a0" "gv$_lock1"@"sel$7")
  115.       full(@"sel$9" "x$ksqeq"@"sel$9")
  116.       full(@"sel$8" "x$kdnssf"@"sel$8")
  117.       end_outline_data
  118.   */

  120. predicate information (identified by operation id):
  121. ---------------------------------------------------

  123.    2 - access("saddr"="s"."addr" and
  124.               to_char(userenv('instance'))||rawtohex("raddr")=to_char("r"."inst_id")||
  125.               rawtohex("r"."addr"))
  126.    4 - filter("s"."inst_id"=userenv('instance'))
  127.    6 - filter("r"."ksqrsidt"='tx')
  128.    9 - filter(userenv('instance') is not null)
  129.   12 - filter(("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  130.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0))
  131.   13 - filter(("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  132.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0))
  133.   14 - filter(("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  134.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0))
  135.   15 - filter(("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  136.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0))
  137.   16 - filter(("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  138.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0))
  139.   17 - filter(("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  140.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0))
  141.   18 - filter(("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  142.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0))
  143.   19 - filter(("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  144.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0))
  145.   20 - filter(("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  146.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0))
  147.   21 - filter(("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  148.               "inst_id"=userenv('instance') and bitand("ksspaflg",1)<>0))

  150. column projection information (identified by operation id):
  151. -----------------------------------------------------------

  153.    1 - (#keys=0) count(*)[22]
  154.    2 - (#keys=2)
  155.    3 - "s"."addr"[raw,8], "r"."addr"[raw,8], "r"."inst_id"[number,22]
  156.    4 - "s"."addr"[raw,8], "s"."inst_id"[number,22]
  157.    5 - (#keys=0) "r"."addr"[raw,8], "r"."inst_id"[number,22]
  158.    6 - "r"."addr"[raw,8], "r"."inst_id"[number,22],
  159.        "r"."ksqrsidt"[varchar2,2]
  160.    7 - "saddr"[raw,8], "raddr"[raw,8]
  161.    8 - strdef[8], strdef[8]
  162.    9 - "saddr"[raw,8], "raddr"[raw,8]
  163.   10 - "saddr"[raw,8], "raddr"[raw,8]
  164.   11 - strdef[8], strdef[8]
  165.   12 - "inst_id"[number,22], "kssobflg"[number,22], "ksqlkres"[raw,8],
  166.        "ksqlkmod"[number,22], "ksqlkreq"[number,22], "ksqlkses"[raw,8]
  167.   13 - "inst_id"[number,22], "kssobflg"[number,22], "ksqlkres"[raw,8],
  168.        "ksqlkmod"[number,22], "ksqlkreq"[number,22], "ksqlkses"[raw,8]
  169.   14 - "inst_id"[number,22], "kssobflg"[number,22], "ksqlkres"[raw,8],
  170.        "ksqlkmod"[number,22], "ksqlkreq"[number,22], "ksqlkses"[raw,8]
  171.   15 - "inst_id"[number,22], "kssobflg"[number,22], "ksqlkres"[raw,8],
  172.        "ksqlkmod"[number,22], "ksqlkreq"[number,22], "ksqlkses"[raw,8]
  173.   16 - "inst_id"[number,22], "kssobflg"[number,22], "ksqlkres"[raw,8],
  174.        "ksqlkmod"[number,22], "ksqlkreq"[number,22], "ksqlkses"[raw,8]
  175.   17 - "inst_id"[number,22], "kssobflg"[number,22], "ksqlkres"[raw,8],
  176.        "ksqlkmod"[number,22], "ksqlkreq"[number,22], "ksqlkses"[raw,8]
  177.   18 - "inst_id"[number,22], "kssobflg"[number,22], "ksqlkres"[raw,8],
  178.        "ksqlkmod"[number,22], "ksqlkreq"[number,22], "ksqlkses"[raw,8]
  179.   19 - "inst_id"[number,22], "kssobflg"[number,22], "ksqlkres"[raw,8],
  180.        "ksqlkmod"[number,22], "ksqlkreq"[number,22], "ksqlkses"[raw,8]
  181.   20 - "inst_id"[number,22], "kssobflg"[number,22], "ksqlkres"[raw,8],
  182.        "ksqlkmod"[number,22], "ksqlkreq"[number,22], "ksqlkses"[raw,8]
  183.   21 - "inst_id"[number,22], "ksspaflg"[number,22], "ksqlkres"[raw,8],
  184.        "ksqlkmod"[number,22], "ksqlkreq"[number,22], "ksqlkses"[raw,8]

破解的办法就是加提示：ordered

说明：
如果从执行联接的sql语句中没有ordered提示，那么优化器将选择联接表的顺序。如果您对优化器不知道的每个表中所选行的数量有所了解，则可能需要使用ordered提示来指定联接顺序。这样的信息可以让您比优化器更好地选择内部和外部表。

当sql将大量表连接在一起（> 5）并且您知道应该始终按特定顺序连接表时，有序提示可能会极大地提高性能。

  1. 11:30:38 sys@orcl1> set autot trace exp stat
  2. 11:30:46 sys@orcl1> select /* rule */ count(*) from v$lock where type = 'tx' and request = 6;
  3.  elapsed: 00:00:00.24

  5. execution plan
  6. ----------------------------------------------------------
  7. plan hash value: 2026431807

  9. -------------------------------------------------
  10. | id | operation | name |
  11. -------------------------------------------------
  12. | 0 | select statement | |
  13. | 1 | sort aggregate | |
  14. | 2 | merge join | |
  15. | 3 | sort join | |
  16. | 4 | merge join | |
  17. | 5 | sort join | |
  18. |* 6 | fixed table full | x$ksqrs |
  19. |* 7 | sort join | |
  20. | 8 | view | gv$_lock |
  21. | 9 | union-all | |
  22. |* 10 | filter | |
  23. | 11 | view | gv$_lock1 |
  24. | 12 | union-all | |
  25. |* 13 | fixed table full| x$kdnssf |
  26. |* 14 | fixed table full| x$ksqeq |
  27. |* 15 | fixed table full | x$ktadm |
  28. |* 16 | fixed table full | x$ktatrfil |
  29. |* 17 | fixed table full | x$ktatrfsl |
  30. |* 18 | fixed table full | x$ktatl |
  31. |* 19 | fixed table full | x$ktstusc |
  32. |* 20 | fixed table full | x$ktstuss |
  33. |* 21 | fixed table full | x$ktstusg |
  34. |* 22 | fixed table full | x$ktcxb |
  35. |* 23 | sort join | |
  36. |* 24 | fixed table full | x$ksuse |
  37. -------------------------------------------------

  39. predicate information (identified by operation id):
  40. ---------------------------------------------------

  42.    6 - filter("r"."ksqrsidt"='tx')
  43.    7 - access(to_char(userenv('instance'))||rawtohex("raddr")=to_char("r
  44.               "."inst_id")||rawtohex("r"."addr"))
  45.        filter(to_char(userenv('instance'))||rawtohex("raddr")=to_char("r
  46.               "."inst_id")||rawtohex("r"."addr"))
  47.   10 - filter(userenv('instance')=userenv('instance'))
  48.   13 - filter("ksqlkreq"=6 and "inst_id"=userenv('instance') and
  49.               ("ksqlkmod"<>0 or "ksqlkreq"<>0) and bitand("kssobflg",1)<>0)
  50.   14 - filter("ksqlkreq"=6 and "inst_id"=userenv('instance') and
  51.               ("ksqlkmod"<>0 or "ksqlkreq"<>0) and bitand("kssobflg",1)<>0)
  52.   15 - filter("inst_id"=userenv('instance') and "ksqlkreq"=6 and
  53.               ("ksqlkmod"<>0 or "ksqlkreq"<>0) and bitand("kssobflg",1)<>0)
  54.   16 - filter("inst_id"=userenv('instance') and "ksqlkreq"=6 and
  55.               ("ksqlkmod"<>0 or "ksqlkreq"<>0) and bitand("kssobflg",1)<>0)
  56.   17 - filter("inst_id"=userenv('instance') and "ksqlkreq"=6 and
  57.               ("ksqlkmod"<>0 or "ksqlkreq"<>0) and bitand("kssobflg",1)<>0)
  58.   18 - filter("inst_id"=userenv('instance') and "ksqlkreq"=6 and
  59.               ("ksqlkmod"<>0 or "ksqlkreq"<>0) and bitand("kssobflg",1)<>0)
  60.   19 - filter("inst_id"=userenv('instance') and "ksqlkreq"=6 and
  61.               ("ksqlkmod"<>0 or "ksqlkreq"<>0) and bitand("kssobflg",1)<>0)
  62.   20 - filter("inst_id"=userenv('instance') and "ksqlkreq"=6 and
  63.               ("ksqlkmod"<>0 or "ksqlkreq"<>0) and bitand("kssobflg",1)<>0)
  64.   21 - filter("inst_id"=userenv('instance') and "ksqlkreq"=6 and
  65.               ("ksqlkmod"<>0 or "ksqlkreq"<>0) and bitand("kssobflg",1)<>0)
  66.   22 - filter("inst_id"=userenv('instance') and "ksqlkreq"=6 and
  67.               ("ksqlkmod"<>0 or "ksqlkreq"<>0) and bitand("ksspaflg",1)<>0)
  68.   23 - access("saddr"="s"."addr")
  69.        filter("saddr"="s"."addr")
  70.   24 - filter("s"."inst_id"=userenv('instance'))

  72. note
  73. -----
  74.    - rule based optimizer used (consider using cbo)


  77. statistics
  78. ----------------------------------------------------------
  79.           0 recursive calls
  80.           1 db block gets
  81.           0 consistent gets
  82.           0 physical reads
  83.           0 redo size
  84.         596 bytes sent via sql*net to client
  85.         520 bytes received via sql*net from client
  86.           2 sql*net roundtrips to/from client
  87.           3 sorts (memory)
  88.           0 sorts (disk)
  89.           1 rows processed

  91. 11:30:48 sys@orcl1>
  92. 11:31:24 sys@orcl1>
  93. 11:31:25 sys@orcl1> select /* ordered */count(*) from v$lock where type = 'tx' and request = 6;
  94. elapsed: 00:00:00.21

  96. execution plan
  97. ----------------------------------------------------------
  98. plan hash value: 3730480328

  100. ---------------------------------------------------------------------------------------
  101. | id | operation | name | rows | bytes | cost (%cpu)| time |
  102. ---------------------------------------------------------------------------------------
  103. | 0 | select statement | | 1 | 53 | 1 (100)| 00:00:01 |
  104. | 1 | sort aggregate | | 1 | 53 | | |
  105. |* 2 | hash join | | 1 | 53 | 1 (100)| 00:00:01 |
  106. |* 3 | hash join | | 1 | 31 | 0 (0)| 00:00:01 |
  107. | 4 | view | gv$_lock | 10 | 120 | 0 (0)| 00:00:01 |
  108. | 5 | union-all | | | | | |
  109. |* 6 | filter | | | | | |
  110. | 7 | view | gv$_lock1 | 2 | 24 | 0 (0)| 00:00:01 |
  111. | 8 | union-all | | | | | |
  112. |* 9 | fixed table full| x$kdnssf | 1 | 64 | 0 (0)| 00:00:01 |
  113. |* 10 | fixed table full| x$ksqeq | 1 | 64 | 0 (0)| 00:00:01 |
  114. |* 11 | fixed table full | x$ktadm | 1 | 64 | 0 (0)| 00:00:01 |
  115. |* 12 | fixed table full | x$ktatrfil | 1 | 64 | 0 (0)| 00:00:01 |
  116. |* 13 | fixed table full | x$ktatrfsl | 1 | 64 | 0 (0)| 00:00:01 |
  117. |* 14 | fixed table full | x$ktatl | 1 | 64 | 0 (0)| 00:00:01 |
  118. |* 15 | fixed table full | x$ktstusc | 1 | 64 | 0 (0)| 00:00:01 |
  119. |* 16 | fixed table full | x$ktstuss | 1 | 64 | 0 (0)| 00:00:01 |
  120. |* 17 | fixed table full | x$ktstusg | 1 | 64 | 0 (0)| 00:00:01 |
  121. |* 18 | fixed table full | x$ktcxb | 1 | 64 | 0 (0)| 00:00:01 |
  122. |* 19 | fixed table full | x$ksuse | 1 | 19 | 0 (0)| 00:00:01 |
  123. |* 20 | fixed table full | x$ksqrs | 1 | 22 | 0 (0)| 00:00:01 |
  124. ---------------------------------------------------------------------------------------

  126. predicate information (identified by operation id):
  127. ---------------------------------------------------

  129.    2 - access(to_char(userenv('instance'))||rawtohex("raddr")=to_char("r"."inst
  130.               _id")||rawtohex("r"."addr"))
  131.    3 - access("saddr"="s"."addr")
  132.    6 - filter(userenv('instance') is not null)
  133.    9 - filter("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  134.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0)
  135.   10 - filter("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  136.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0)
  137.   11 - filter("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  138.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0)
  139.   12 - filter("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  140.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0)
  141.   13 - filter("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  142.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0)
  143.   14 - filter("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  144.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0)
  145.   15 - filter("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  146.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0)
  147.   16 - filter("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  148.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0)
  149.   17 - filter("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  150.               "inst_id"=userenv('instance') and bitand("kssobflg",1)<>0)
  151.   18 - filter("ksqlkreq"=6 and ("ksqlkmod"<>0 or "ksqlkreq"<>0) and
  152.               "inst_id"=userenv('instance') and bitand("ksspaflg",1)<>0)
  153.   19 - filter("s"."inst_id"=userenv('instance'))
  154.   20 - filter("r"."ksqrsidt"='tx')


  157. statistics
  158. ----------------------------------------------------------
  159.           1 recursive calls
  160.           1 db block gets
  161.           0 consistent gets
  162.           0 physical reads
  163.           0 redo size
  164.         596 bytes sent via sql*net to client
  165.         520 bytes received via sql*net from client
  166.           2 sql*net roundtrips to/from client
  167.           0 sorts (memory)
  168.           0 sorts (disk)
  169.           1 rows processed
从300多秒降低到 0.1秒

但是监控系统是“成熟”商业软件，不能改写语句，怎么办呢？
设置触发器？还是设置某个神奇的隐含参数？


以下方法有的情况下有效：
  1. begin
  2.  dbms_stats.gather_table_stats('sys','x$ksuse',method_opt=>'for all columns size 1');
  3.  dbms_stats.gather_table_stats('sys','x$ksqrs',method_opt=>'for all columns size 1');
  4. end;
  5. /
对于视图内的合并连接卡迪森，之前的方法
alter session set "_optimizer_mjc_enabled"=flase;不起作用

阅读(1350) | 评论(0) | 转发(0) |
0

上一篇：log file switch (checkpoint incomplete)案例

下一篇：oracle 11g 客户端安装

给主人留下些什么吧！~~
| | | | |

凯发app官方网站 copyright 2001-2010 chinaunix.net all rights reserved 北京皓辰网域网络信息技术有限公司. 凯发k8官网下载客户端中心的版权所有

感谢所有关心和支持过chinaunix的朋友们
")); function link(t){ var href= $(t).attr('href'); href ="?url=" encodeuricomponent(location.href); $(t).attr('href',href); //setcookie("returnouturl", location.href, 60, "/"); }
网站地图