oracle 11g enq: JI – contention等待事件

最近使用物化视图同步的环境在大量刷新的时候频繁出现enq: JI – contention等待事件，经查：

JI enqueue is acquired in exclusive mode on the mview base (container) table when more than one session refresh the same materialzed view. It ensures that two or more refresh processes do not try to refresh the same object.

Sessions waiting on this event are waiting on locks held during materialized view operations (such as refresh, alter) to prevent concurrent operations on the same materialized view.

Solutions

A materialized view cannot be fast refreshed more than once in a given period because it is serialized during the commit phase. Ensure that only one session at a time is performing the refreshes. If there is more than one session, the first session will work normally but the subsequent sessions will wait on “enq: JI – contention”.

Waits on this event can also be caused by on-commit time logic within the materialized view. Normally when a session updates record 1 and commits and then another session updates record 2 and commits, they do not have to wait for each other. However, when using an on commit-time fast refreshable materialized view on top of the table, we do have to wait when two sessions do totally unrelated transactions concurrently against the same table. This is not a problem when the table is modified infrequently or only by a single session, but it can be a big problem when applied to a table that performs a lot of modifications concurrently. Be sure to use on commit-time fast refreshable materialized views for implementing business rules only on tables that are not concurrently accessed or infrequently changed.

Solution:

First we have to check which session hold the lock (LMODE) and which process requests the lock(REQUEST). We can easily check it from v$lock.

LMODE and REQUEST Column description from v$lock.

LMODE

NUMBER

Lock mode in which the session holds the lock:

0 - none
1 - null (NULL)
2 - row-S (SS)
3 - row-X (SX)
4 - share (S)
5 - S/Row-X (SSX)
6 - exclusive (X)

REQUEST

NUMBER

Lock mode in which the process requests the lock:

0 - none
1 - null (NULL)
2 - row-S (SS)
3 - row-X (SX)
4 - share (S)
5 - S/Row-X (SSX)
6 - exclusive (X)

select

nvl(S.USERNAME,'Internal') username,S.MACHINE,s.SERIAL#,

L.SID,

nvl(S.TERMINAL,'None') terminal,

decode(command,

0,'None',decode(l.id2,0,U1.NAME||'.'||substr(T1.NAME,1,20),'None')) tab,

decode(command,

0,'BACKGROUND',

1,'Create Table',

2,'INSERT',

3,'SELECT',

4,'CREATE CLUSTER',

5,'ALTER CLUSTER',

6,'UPDATE',

7,'DELETE',

8,'DROP',

9,'CREATE INDEX',

10,'DROP INDEX',

11,'ALTER INDEX',

12,'DROP TABLE',

13,'CREATE SEQUENCE',

14,'ALTER SEQUENCE',

15,'ALTER TABLE',

16,'DROP SEQUENCE',

17,'GRANT',

18,'REVOKE',

19,'CREATE SYNONYM',

20,'DROP SYNONYM',

21,'CREATE VIEW',

22,'DROP VIEW',

23,'VALIDATE INDEX',

24,'CREATE PROCEDURE',

25,'ALTER PROCEDURE',

26,'LOCK TABLE',

27,'NO OPERATION',

28,'RENAME',

29,'COMMENT',

30,'AUDIT',

31,'NOAUDIT',

32,'CREATE EXTERNAL DATABASE',

33,'DROP EXTERNAL DATABASE',

34,'CREATE DATABASE',

35,'ALTER DATABASE',

36,'CREATE ROLLBACK SEGMENT',

37,'ALTER ROLLBACK SEGMENT',

38,'DROP ROLLBACK SEGMENT',

39,'CREATE TABLESPACE',

40,'ALTER TABLESPACE',

41,'DROP TABLESPACE',

42,'ALTER SESSION',

43,'ALTER USER',

44,'COMMIT',

45,'ROLLBACK',

46,'SAVEPOINT',

47,'PL/SQL EXECUTE',

48,'SET TRANSACTION',

49,'ALTER SYSTEM SWITCH LOG',

50,'EXPLAIN',

51,'CREATE USER',

52,'CREATE ROLE',

53,'DROP USER',

54,'DROP ROLE',

55,'SET ROLE',

56,'CREATE SCHEMA',

57,'CREATE CONTROL FILE',

58,'ALTER TRACING',

59,'CREATE TRIGGER',

60,'ALTER TRIGGER',

61,'DROP TRIGGER',

62,'ANALYZE TABLE',

63,'ANALYZE INDEX',

64,'ANALYZE CLUSTER',

65,'CREATE PROFILE',

66,'DROP PROFILE',

67,'ALTER PROFILE',

68,'DROP PROCEDURE',

69,'DROP PROCEDURE',

70,'ALTER RESOURCE COST',

71,'CREATE SNAPSHOT LOG',

72,'ALTER SNAPSHOT LOG',

73,'DROP SNAPSHOT LOG',

74,'CREATE SNAPSHOT',

75,'ALTER SNAPSHOT',

76,'DROP SNAPSHOT',

79,'ALTER ROLE',

85,'TRUNCATE TABLE',

86,'TRUNCATE CLUSTER',

87,'-',

88,'ALTER VIEW',

89,'-',

90,'-',

91,'CREATE FUNCTION',

92,'ALTER FUNCTION',

93,'DROP FUNCTION',

94,'CREATE PACKAGE',

95,'ALTER PACKAGE',

96,'DROP PACKAGE',

97,'CREATE PACKAGE BODY',

98,'ALTER PACKAGE BODY',

99,'DROP PACKAGE BODY',

command||' - ???') COMMAND,

decode(L.LMODE,1,'No Lock',

2,'Row Share',

3,'Row Exclusive',

4,'Share',

5,'Share Row Exclusive',

6,'Exclusive','NONE') lmode,

decode(L.REQUEST,1,'No Lock',

2,'Row Share',

3,'Row Exclusive',

4,'Share',

5,'Share Row Exclusive',

6,'Exclusive','NONE') request,

l.id1||'-'||l.id2 Laddr,

l.type||' - '||

decode(l.type,

'BL','Buffer hash table instance lock',

'CF',' Control file schema global enqueue lock',

'CI','Cross-instance function invocation instance lock',

'CS','Control file schema global enqueue lock',

'CU','Cursor bind lock',

'DF','Data file instance lock',

'DL','Direct loader parallel index create',

'DM','Mount/startup db primary/secondary instance lock',

'DR','Distributed recovery process lock',

'DX','Distributed transaction entry lock',

'FI','SGA open-file information lock',

'FS','File set lock',

'HW','Space management operations on a specific segment lock',

'IN','Instance number lock',

'IR','Instance recovery serialization global enqueue lock',

'IS','Instance state lock',

'IV','Library cache invalidation instance lock',

'JQ','Job queue lock',

'KK','Thread kick lock',

'MB','Master buffer hash table instance lock',

'MM','Mount definition gloabal enqueue lock',

'MR','Media recovery lock',

'PF','Password file lock',

'PI','Parallel operation lock',

'PR','Process startup lock',

'PS','Parallel operation lock',

'RE','USE_ROW_ENQUEUE enforcement lock',

'RT','Redo thread global enqueue lock',

'RW','Row wait enqueue lock',

'SC','System commit number instance lock',

'SH','System commit number high water mark enqueue lock',

'SM','SMON lock',

'SN','Sequence number instance lock',

'SQ','Sequence number enqueue lock',

'SS','Sort segment lock',

'ST','Space transaction enqueue lock',

'SV','Sequence number value lock',

'TA','Generic enqueue lock',

'TD','DDL enqueue lock',

'TE','Extend-segment enqueue lock',

'TM','DML enqueue lock',

'TO','Temporary Table Object Enqueue',

'TT','Temporary table enqueue lock',

'TX','Transaction enqueue lock',

'UL','User supplied lock',

'UN','User name lock',

'US','Undo segment DDL lock',

'WL','Being-written redo log instance lock',

'WS','Write-atomic-log-switch global enqueue lock',

'TS',decode(l.id2,0,'Temporary segment enqueue lock (ID2=0)',

'New block allocation enqueue lock (ID2=1)'),

'LA','Library cache lock instance lock (A=namespace)',

'LB','Library cache lock instance lock (B=namespace)',

'LC','Library cache lock instance lock (C=namespace)',

'LD','Library cache lock instance lock (D=namespace)',

'LE','Library cache lock instance lock (E=namespace)',

'LF','Library cache lock instance lock (F=namespace)',

'LG','Library cache lock instance lock (G=namespace)',

'LH','Library cache lock instance lock (H=namespace)',

'LI','Library cache lock instance lock (I=namespace)',

'LJ','Library cache lock instance lock (J=namespace)',

'LK','Library cache lock instance lock (K=namespace)',

'LL','Library cache lock instance lock (L=namespace)',

'LM','Library cache lock instance lock (M=namespace)',

'LN','Library cache lock instance lock (N=namespace)',

'LO','Library cache lock instance lock (O=namespace)',

'LP','Library cache lock instance lock (P=namespace)',

'LS','Log start/log switch enqueue lock',

'PA','Library cache pin instance lock (A=namespace)',

'PB','Library cache pin instance lock (B=namespace)',

'PC','Library cache pin instance lock (C=namespace)',

'PD','Library cache pin instance lock (D=namespace)',

'PE','Library cache pin instance lock (E=namespace)',

'PF','Library cache pin instance lock (F=namespace)',

'PG','Library cache pin instance lock (G=namespace)',

'PH','Library cache pin instance lock (H=namespace)',

'PI','Library cache pin instance lock (I=namespace)',

'PJ','Library cache pin instance lock (J=namespace)',

'PL','Library cache pin instance lock (K=namespace)',

'PK','Library cache pin instance lock (L=namespace)',

'PM','Library cache pin instance lock (M=namespace)',

'PN','Library cache pin instance lock (N=namespace)',

'PO','Library cache pin instance lock (O=namespace)',

'PP','Library cache pin instance lock (P=namespace)',

'PQ','Library cache pin instance lock (Q=namespace)',

'PR','Library cache pin instance lock (R=namespace)',

'PS','Library cache pin instance lock (S=namespace)',

'PT','Library cache pin instance lock (T=namespace)',

'PU','Library cache pin instance lock (U=namespace)',

'PV','Library cache pin instance lock (V=namespace)',

'PW','Library cache pin instance lock (W=namespace)',

'PX','Library cache pin instance lock (X=namespace)',

'PY','Library cache pin instance lock (Y=namespace)',

'PZ','Library cache pin instance lock (Z=namespace)',

'QA','Row cache instance lock (A=cache)',

'QB','Row cache instance lock (B=cache)',

'QC','Row cache instance lock (C=cache)',

'QD','Row cache instance lock (D=cache)',

'QE','Row cache instance lock (E=cache)',

'QF','Row cache instance lock (F=cache)',

'QG','Row cache instance lock (G=cache)',

'QH','Row cache instance lock (H=cache)',

'QI','Row cache instance lock (I=cache)',

'QJ','Row cache instance lock (J=cache)',

'QL','Row cache instance lock (K=cache)',

'QK','Row cache instance lock (L=cache)',

'QM','Row cache instance lock (M=cache)',

'QN','Row cache instance lock (N=cache)',

'QO','Row cache instance lock (O=cache)',

'QP','Row cache instance lock (P=cache)',

'QQ','Row cache instance lock (Q=cache)',

'QR','Row cache instance lock (R=cache)',

'QS','Row cache instance lock (S=cache)',

'QT','Row cache instance lock (T=cache)',

'QU','Row cache instance lock (U=cache)',

'QV','Row cache instance lock (V=cache)',

'QW','Row cache instance lock (W=cache)',

'QX','Row cache instance lock (X=cache)',

'QY','Row cache instance lock (Y=cache)',

'QZ','Row cache instance lock (Z=cache)','????') Lockt,

SQ.SQL_TEXT

from V$LOCK L,

V$SESSION S,

SYS.USER$ U1,

SYS.OBJ$ T1,

V$SQL SQ

where L.SID = S.SID

and S.SQL_ADDRESS = SQ.ADDRESS

and T1.OBJ# = decode(L.ID2,0,L.ID1,1)

and U1.USER# = T1.OWNER#

and S.TYPE != 'BACKGROUND'

and l.type like '%JI%'

order by 1,2,5;

USERNAME	MACHINE	SERIAL#	SID	TERMINAL	TAB	COMMAND	LMODE	REQUEST	LADDR	LOCKT	SQL_TEXT
BIDATA	db.test.com	21,031	254	None	BIDATA.SESSION_LOG_DAY_	PL/SQL EXECUTE	NONE	Exclusive	640374-0	JI - ????	BEGIN DBMS_MVIEW.REFRESH ('WEB_SESSION_LOG_DAY_MV', 'f'); END;
BIDATA	db.test.com	10,143	7	pts/5	BIDATA.SESSION_LOG_DAY_	INSERT	Exclusive	NONE	640374-0	JI - ????	/* MV_REFRESH (INS) /INSERT /+ BYPASS_RECURSIVE_CHECK / INTO "BIDATA"."WEB_SESSION_LOG_DAY_MV"("IPX_DATE","CONSUMERMARKETID","CONSUMEROPERATORID","CONTENTPROVIDERID","SESSIONTYPE","WASWHITELABEL","FINALSTATE","ERRORCODE","BRANDNAME","MODELNAME","MOBILEBROWSER","MOBILEBROWSERVERSION","CONTENTPROVIDERSERVICEID","NUMTRANSACTIONS","CNT_NUMTX","COUNT()") SELECT "TDIM"."DAY_KEY","WSLMV"."CONSUMERMARKETID","WSLMV"."CONSUMEROPERATORID","WSLMV"."CONTENTPROVIDERID","WSLMV"."SESSIONTYPE","WSLMV"."WASWHITELABEL","WSLMV"."FINALSTATE","WSLMV"."ERRORCODE","WSLMV"."BRANDNAME","WSLMV"."MODELNAME","WSLMV"."MOBILEBROWSER","WSLMV"."MOBILEBROWSERVERSION","WSLMV"."CONTENTPROVIDERSERVICEID",SUM("WSLMV"."NUMTRANSACTIONS"),COUNT("WSLMV"."NUMTRANSACTIONS"),COUNT(*) FROM "WEB_SESSION_LOG_HOUR_MV" "WSLMV","TIME_DIMENSION" "TDIM" WHERE "WSLMV"."IPX_DATE"="TDIM"."DAY_KEY" GROUP BY "TDIM"."DAY_KEY","WSLMV"."CONSUMERMARKETID","WSLMV"."CONSUMEROPERATORID","WSLMV"."CONTENTPROVIDERID","WSLMV"."SESSIONTYPE","WSLMV"."

If the JI enqueue holder is an intended refresh session then the other session that trying to refresh it need to wait until first one finishes. If the JI enqueuer holder session stuck for some reason then you may kill it so the second session can proceed.

Example:

SQL> alter system kill session '254,21031';

System altered.

Don’t refresh the same Mview object by many sessions at the same time.

For more information please check Oracle Doc ID 1358453.1

也就是对于同一个物化视图基表，不能过于频繁的刷新，尤其不能并发进行刷新，我们的刚好就是有频繁的定时刷新+手工刷新，重叠之后就出现这个问题了。让开发调整为要么手工、要么自动，不要交叉进行。

oracle 11g enq: JI – contention等待事件的更多相关文章

enq: DX – contention等待事件解决方法
前几日,一测试环境在dblink单表同步的时候(不管怎么说,目前仍然是同构数据库同步性能最快的方法,别听网上的扯淡,无论goldengate还是java层,都是比较慢的),某张表一直同步不过去,看了一 ...
Oracle 11g direct path read 等待事件的理解
在Oracle 11g中,全表扫描可能使用direct path read方式,绕过buffer cache,这样的全表扫描就是物理读了. 在10g中,都是通过gc buffer来读的,所以不存在di ...
enq: TX - row lock contention“等待事件的处理
enq: TX - row lock contention“等待事件的处理 session1: SQL> conn scott/triger Connected. SQL> CRE ...
Oracle常见的几种等待事件
1. CPU time CPU time其实不是真正的等待事件.是衡量CPU是否瓶颈的一个重要指标.一般来讲,一个良好的系统,CPU TIME 应该排在TOP 5 TIME Event的最前面. 当然 ...
Oracle 常见的33个等待事件
一．等待事件的相关知识: 1.1 等待事件主要可以分为两类,即空闲(IDLE)等待事件和非空闲(NON-IDLE)等待事件. 1). 空闲等待事件指Oracle正等待某种工作,在诊断和优化数据库的时 ...
Oracle常见的33个等待事件
Buffer busy waits 原因: 当一个会话试图修改一个数据块,但这个数据块正在被另一个会话修改时. 当一个会话需要读取一个数据块,但这个数据块正在被另一个会话读 ...
【参考】查找Oracle最高的几个等待事件以及锁的信息
1.通过操作系统的命令找到系统资源的bottleneck,如:CPU, Memory, I/O, Network 同时主要关注IOWait, PI/PO, Memory的使用情况 2.通过查询v$s ...
【等待事件】序列等待事件总结（enq: SQ - contention、row cache lock、DFS lock handle和enq: SV - contention）
[等待事件]序列等待事件总结(enq: SQ - contention.row cache lock.DFS lock handle和enq: SV - contention) 1 BLOG文档结 ...
等待事件：enq: HW - contention和enq: TM - contention
今天生成了生产库前几日的AWR报告,发现等待事件中出现了一个陌生的event--enq: HW - contention,google一下是ASSM(Auto Segment Space Manage ...

随机推荐

python接口测试-充值
import requests import json import unittest import HTMLTestRunner telphone =18200717087 #参数化手机号码 ur1 ...
IdentityServer3:.NET开源OpenID和OAuth2架构
简介大多数软件的相互沟通图:客户端与Web应用程序的访问.应用与Web api.api与api……相互沟通则需要授权.身份验证 IdentityServer3的功能:Web认证.SSO单点登录.We ...
js中两个!!的理解
在js中经常有两个!!出现,经常让人难以理解 (function () { var a = 10; var b = 20; function add(num1, num2) { var num1 = ...
Navicat Premium 安装与激活破解版简单操作（原）
首先下载navicate程序以及破解文件,这里一并存到了百度网盘直接下载即可链接:https://pan.baidu.com/s/11ptFmsV1o3B5oB00zm2NdQ 密码:yw82 解压 ...
whu 643 Soul Artist(二维BIT 区间更新,单点查询)
Soul Artis [题目链接]Soul Artis [题目类型]二维BIT &题解: 二维区间更新和一维相比,要容斥一下,更新一块区间就是更新4个点. 还有这个我先是写了2*n^2logn ...
jQuery-使用hover(fn,fn)函数监听mouseover和mouseout两个事件
<!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8&quo ...
c# 集合中有数字、字符的Orderby排序
string[] things= new string[] { "105", "101", "102", "103", ...
C#6.0中10大新特性的应用和总结
微软发布C#6.0.VS2015等系列产品也有一段时间了,但是网上的教程却不多,这里真对C#6.0给大家做了一些示例,分享给大家. 微软于2015年7月21日发布了Visual Studio 20 ...
Vue系列之 => 通过vue-resource发起ajax请求
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8&quo ...
计算属性（computed）、方法（methods）和侦听属性（watch）的区别与使用场景
1,computed 能实现的,methods 肯定也能够实现. 2,不同之处在于,computed 是基于他的依赖进行缓存的,computed 只有在他的的相关依赖发生改变的时候才会重新计算. 如果 ...

oracle 11g enq: JI – contention等待事件

oracle 11g enq: JI – contention等待事件的更多相关文章

随机推荐

热门专题