當前位置：首頁 > 运维知识 > 数据库 >内容正文

数据库

oracle数据库延迟执行,如何诊断oracle数据库运行缓慢或hang住的问题

發布時間：2024/7/5 数据库 28 豆豆

生活随笔收集整理的這篇文章主要介紹了 oracle数据库延迟执行,如何诊断oracle数据库运行缓慢或hang住的问题小編覺得挺不錯的,現在分享給大家,幫大家做個參考.

為了診斷oracle運行緩慢的問題首先要決定收集哪些診斷信息,可以采取下面的診斷方法:

1.數據庫運行緩慢這個問題是常見還是在特定時間出現

如果數據庫運行緩慢是一個常見的問題那么可以在問題出現的時候收集這個時期的awr或者statspack報告(通常收集時間間隔是一個小時).生成awr報告的方法如下:

awr是通過sys用戶來收集持久系統性能統計信息并且這些信息保存在sysaux表空間.缺省情況下快照是一個小時生成一次并且保留7天.awr報告輸出了基于指定快照之間的一系列的統計信息用于性能分析和調查其它問題.

運行基本的報告

可以執行下面的腳本來生成一個awr報告:

$ORACLE_HOME/rdbms/admin/awrrpt.sql

可以根據自己收集awr報告的原因來決定生成一個快照的時間間隔也可以指定生成awr報告的格式(text或html).

生成各種類型的awr報告

可以根據各種要求來運行各種sql腳本來生成各種類型的awr報告.每一種報告都有兩種格式(txt或html):

awrrpt.sql

顯示指定快照范圍內的各種統計信息

awrrpti.sql

顯示一個特定數據庫和實例中指定快照范圍內的各種統計信息

awrsqrpt.sql

顯示一個指定快照范圍內的一個特定的sql語句的統計信息.運行這個報告是為了檢查或調查一個特定sql語句的性能

awrsqrpi.sql

顯示一個特定sql在指定快照范圍內的的統計信息.

awrddrpt.sql

比較在兩個選擇的時間間隔期間內詳細的性能數據和配置情況

awrddrpi.sql

在一個特定的數據庫和平共處實例中比較在兩個選擇的時間間隔期間內詳細的性能數和配置情況

各種awr相關的操作

怎樣修改awr快照的設置:

BEGIN

DBMS_WORKLOAD_REPOSITORY.modify_snapshot_settings(

retention => 43200, -- Minutes (43200 = 30 Days).

-- Current value retained if NULL.

interval => 30); -- Minutes. Current value retained if NULL.

END;

創建一個awr基線:

BEGIN

DBMS_WORKLOAD_REPOSITORY.create_baseline (

start_snap_id => 10,

end_snap_id => 100,

baseline_name => 'AWR First baseline');

END;

在oracle11G中引入了一個新的dbms_workload_repository.create_baseline_template過程來創建一個awr基線模板

BEGIN

DBMS_WORKLOAD_REPOSITORY.CREATE_BASELINE_TEMPLATE (

start_time => to_date('&start_date_time','&start_date_time_format'),

end_time => to_date('&end_date_time','&end_date_time_format'),

baseline_name => 'MORNING',

template_name => 'MORNING',

expiration => NULL ) ;

END;

"expiration=>NULL"這意味著這個基線將永遠保持有效.

刪除一個awr基線

BEGIN

DBMS_WORKLOAD_REPOSITORY.DROP_BASELINE (

baseline_name => 'AWR First baseline');

END;

也能從一個老的數據庫中刪除一個awr基線:

BEGIN

DBMS_WORKLOAD_REPOSITORY.DROP_BASELINE (baseline_name => 'peak baseline',

cascade => FALSE, dbid => 3310949047);

END;

刪除awr快照:

BEGIN

DBMS_WORKLOAD_REPOSITORY.drop_snapshot_range(

(low_snap_id=>40,

High_snap_id=>80);

END;

也可能基于報告時間期間對創建和刪除的awr基線指定一個模板:

BEGIN

DBMS_WORKLOAD_REPOSITORY.CREATE_BASELINE_TEMPLATE (

day_of_week => 'MONDAY',

hour_in_day => 9,

duration => 3,

start_time => to_date('&start_date_time','&start_date_time_format'),

end_time => to_date('&end_date_time','&end_date_time_format'),

baseline_name_prefix => 'MONDAY_MORNING'

template_name => 'MONDAY_MORNING',

expiration => 30 );

END;

將會在'&start_date_time'到'&end_date_time'期間的每一個星期一都會生成基線

手動生成的一個awr快照:

BEGIN

DBMS_WORKLOAD_REPOSITORY.create_snapshot();

END;

工作負載資料檔案庫視圖:

V$ACTIVE_SESSION_HISTORY - 顯示歷史活動會話信息每秒抽樣一樣

V$METRIC - 顯示度量標準信息

V$METRICNAME - 顯示與每個度量標準組相關的度量標準

V$METRIC_HISTORY - 顯示歷史度量標準

V$METRICGROUP - 顯示所有的度量標準組

DBA_HIST_ACTIVE_SESS_HISTORY - 顯示歷史活動會話的詳細信息

DBA_HIST_BASELINE - 顯示基線信息

DBA_HIST_DATABASE_INSTANCE - 顯示數據庫環境信息

DBA_HIST_SNAPSHOT - 顯示快照信息

DBA_HIST_SQL_PLAN - 顯示sql執行計劃

DBA_HIST_WR_CONTROL - 顯示awr設置情況

如果數據庫運行緩慢在特定時間出現那么可以當問題存在時生成一個awr或statspack報告,報告的時間間隔包含了問題出現的時間.另外為了比較可以收集沒有出現問題而時間間隔相同的數據庫正常運行的報告這樣可以對報告進行比較.

2.數據庫緩慢它影響的是一個會話,幾個會話還是所有會話

如果數據庫緩慢它影響的是一個會話或幾個會話可以對這個會話或幾個會話進行10046跟蹤

如果數據庫緩慢它影響的是所有會話可以收集awr或statspack報告

執行10046跟蹤的方法如下:

收集10046跟蹤文件

10046事件是一種標準的方法用來對oracle會話收集擴展的sql_trace信息

對于查詢性能問題來說通常要求記錄查詢的等待和綁定變量信息.這可以使用級別為12的10046跟蹤來完成.下面的例子說明了在各種情況下設置10046事件.

跟蹤文件的位置

在oracle11g及以上版本中引入了新的診斷架構,跟蹤和核心文件存儲的位置由diagnostic_dest初始化參數來控制.可以使用下面的命令來顯示:

sys@JINGYONG> show parameter diagnostic_dest

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

diagnostic_dest string /u01/app/oracle

注意:在有些例子中可能設置了'tracefile_identifier'來幫助找到輸出的跟蹤文件

會話跟蹤

可以在用戶會話執行sql語句之前對會話啟用跟蹤,在會話級別收集10046跟蹤

sys@JINGYONG> alter session set timed_statistics=true;

會話已更改。

sys@JINGYONG> alter session set statistics_level=all;

會話已更改。

sys@JINGYONG> alter session set max_dump_file_size=unlimited;

會話已更改。

sys@JINGYONG> alter session set events '10046 trace name context forever,level 1

2';

會話已更改。

sys@JINGYONG> select * from dual;

sys@JINGYONG>exit

如果會話沒有退出可以執行以下語句來禁用10046跟蹤

sys@JINGYONG> alter session set events '10046 trace name context off';

會話已更改。

sys@JINGYONG> select * from v$diag_info ;

INST_ID NAME

---------- ----------------------------------------------------------------

VALUE

--------------------------------------------------------------------------------

----------------------------------------

1 Diag Enabled

TRUE

1 ADR Base

/u01/app/oracle

1 ADR Home

/u01/app/oracle/diag/rdbms/jingyong/jingyong

1 Diag Trace

/u01/app/oracle/diag/rdbms/jingyong/jingyong/trace

1 Diag Alert

/u01/app/oracle/diag/rdbms/jingyong/jingyong/alert

1 Diag Incident

/u01/app/oracle/diag/rdbms/jingyong/jingyong/incident

1 Diag Cdump

/u01/app/oracle/diag/rdbms/jingyong/jingyong/cdump

1 Health Monitor

/u01/app/oracle/diag/rdbms/jingyong/jingyong/hm

1 Default Trace File

/u01/app/oracle/diag/rdbms/jingyong/jingyong/trace/jingyong_ora_2572_10046.trc

1 Active Problem Count

1 Active Incident Count

已選擇11行。

sys@JINGYONG> select * from v$diag_info where name='Default Trace File';

INST_ID NAME

---------- ----------------------------------------------------------------

VALUE

--------------------------------------------------------------------------------

----------------------------------------

1 Default Trace File

/u01/app/oracle/diag/rdbms/jingyong/jingyong/trace/jingyong_ora_2572_10046.trc

注意:如果會話不是徹底的關閉和禁用跟蹤那么重要的跟蹤信息可能會從跟蹤文件中丟失.

注意:這里statistics_level=all因此它會在這種情況下收集一定程度的統計信息.這個參數有三個參數值.all,typical,basic.為了診斷性能問題會要求獲得一定程度的統計信息.設置為all可能是不必要的但可以使用typical以此來獲得全面的診斷信息.

跟蹤一個已經啟動的進程

如果要跟蹤一個已經存在的會話可以使用oradebug來連接到會話初始化10046跟蹤

1.通過某種方法來確定要被跟蹤的會話

例如在sql*plus中啟動一個會話然后找到這個會話的操作系統進行id(spid):

select p.PID,p.SPID,s.SID

from v$process p,v$session s

where s.paddr = p.addr

and s.sid = &SESSION_ID

SPID是操作系統進程標識符

PID是oracle進程標識符

如果你不知道要不得被跟蹤會話的sid可以使用類似于下面的查詢來幫助你識別這個會話:

column line format a79

set heading off

select 'ospid: ' || p.spid ||' pid: '||p.pid || ' # ''' ||s.sid||','||s.serial#||''' '||

s.osuser || ' ' ||s.machine ||' '||s.username ||' '||s.program line

from v$session s , v$process p

where p.addr = s.paddr

and s.username <> ' ';

執行結果如下:

sys@JINGYONG> column line format a79

sys@JINGYONG> set heading off

sys@JINGYONG> select 'ospid: ' || p.spid || ' # ''' ||s.sid||','||s.serial#||'''

'||

2 s.osuser || ' ' ||s.machine ||' '||s.username ||' '||s.program line

3 from v$session s , v$process p

4 where p.addr = s.paddr

5 and s.username <> ' ';

ospid: 2529 # '30,32' Administrator WORKGROUP\JINGYONG SYS sqlplus.exe

注意:在oracle12c中對于多線程進程,在v$process視圖中加入了新的列stid來找到特定的線程.因為oracle會組合多個進程到一個單獨的ospid中.為了找到這個特定的線程使用下面的語法:

oradebug setospid

2.當確定進程的操作系統進程ID后然后可以使用下面的語句來初始化跟蹤:

假設要被跟蹤進程的操作系統進程ID是2529

SQL>connect / as sysdba

sys@JINGYONG> oradebug setospid 2529

Oracle pid: 21, Unix process pid: 2529, image: oracle@jingyong

sys@JINGYONG> oradebug unlimit

已處理的語句

sys@JINGYONG> oradebug event 10046 trace name context forever,level 12

已處理的語句

sys@JINGYONG> select * from dual;

sys@JINGYONG> oradebug event 10046 trace name context off

已處理的語句

sys@JINGYONG> oradebug tracefile_name

/u01/app/oracle/diag/rdbms/jingyong/jingyong/trace/jingyong_ora_2529.trc

注意:連接到一個會話也可以使用oradebug setorapid

在這種情況下PID(oracle進程標識符)將被使用(而不是使用SPID):

sys@JINGYONG> oradebug setorapid 21

Oracle pid: 21, Unix process pid: 2529, image: oracle@jingyong

從顯示的信息可知道使用oradebug setorapid 21與oradebug set0spid 2529是一樣的

sys@JINGYONG> oradebug unlimit

已處理的語句

sys@JINGYONG> oradebug event 10046 trace name context forever,level 12

已處理的語句

sys@JINGYONG> select sysdate from dual;

11-11月-13

sys@JINGYONG> oradebug event 10046 trace name context off

已處理的語句

sys@JINGYONG> oradebug tracefile_name

/u01/app/oracle/diag/rdbms/jingyong/jingyong/trace/jingyong_ora_2529.trc

oradebug setospid

跟蹤產生的跟蹤文件名稱類似于_.trc

實例級別的跟蹤

注意:在實例級別啟用跟蹤因為每一個會話都會被跟蹤這樣對性能是有影響的

在設置這個跟蹤參數后產生的每一個會話都會被跟蹤斷開的會話將不會被跟蹤

設置系統級別的10046跟蹤是用于當出現了一個問題會話但不能提前識別這個會話的情況下.在這種情況下跟蹤可以被短時間地啟用,這個問題可能會記錄到跟蹤文件中然后禁用跟蹤在生成的跟蹤文件中找到這個問題的原因

啟用系統級別的10046跟蹤:

alter system set events '10046 trace name context forever,level 12';

對所有會話禁有系統級別的10046跟蹤:

alter system set events '10046 trace name context off';

初始化參數的設置:

當實例重新啟動后對每一個會話啟用10046跟蹤.

event="10046 trace name context forever,level 12"

要禁用實例級別的10046跟蹤可以刪除這個初始化參數然后重啟實例或者使用alter system語句

alter system set events '10046 trace name context off';

編寫登錄觸發器

在有些情況下可能要跟蹤特定用戶的會話活動在這種情況下可以編寫一個登錄觸發器來實現例如:

CREATE OR REPLACE TRIGGER SYS.set_trace

AFTER LOGON ON DATABASE

WHEN (USER like '&USERNAME')

DECLARE

lcommand varchar(200);

BEGIN

EXECUTE IMMEDIATE 'alter session set tracefile_identifier=''From_Trigger''';

EXECUTE IMMEDIATE 'alter session set statistics_level=ALL';

EXECUTE IMMEDIATE 'alter session set max_dump_file_size=UNLIMITED';

EXECUTE IMMEDIATE 'alter session set events ''10046 trace name context forever, level 12''';

END set_trace;

注意:為了能跟蹤會話用戶執行觸發器需要顯式的被授予'alter session'權限:

grant alter session to username;

使用SQLT來收集跟蹤信息

什么是SQLTXPLAIN(SQLT)

SQLTXPLAIN也叫作SQLT,它是由專業的oracle服務技術中心提供了一個工具.SQLT輸入一個SQL語句后它會輸出一組診斷文件.這些診斷文件會被用來診斷性能低下的sql語句.SQLT連接到數據庫并收集執行,基于成本優化的統計信息,方案對象元數據,性能統計,配置參數和類似影響SQL性能的元素.

使用SQLTXPLAIN的Xecute選項可以生成10046跟蹤作為SQLT輸出的一部分.

使用dbms_monitor包來進行跟蹤

dbms_monitor是一個新的跟蹤包.跟蹤基于特定的客戶端標識符或者服務名,模塊名和操作名的組合形式來啟用診斷和工作負載管理.在有些情況下可能會生成多個跟蹤文件(例如對于一個模塊啟用服務級別的跟蹤)使用新的trcsess工具來掃描所有的跟蹤文件并將它們合成一個跟蹤文件.在合并這一組跟蹤文件后可以使用標準跟蹤文件分析方法進行分析

查看啟用的跟蹤

可以查詢dba_enabled_traces來檢測什么跟蹤被啟用了.

例如:

sys@JINGYONG>select trace_type, primary_id, QUALIFIER_ID1, waits, binds

from DBA_ENABLED_TRACES;

TRACE_TYPE PRIMARY_ID QUALIFIER_ID1 WAITS BINDS

---------------------- --------------- ------------------ -------- -------

SERVICE_MODULE SYS$USERS SQL*Plus TRUE FALSE

CLIENT_ID HUGO TRUE FALSE

SERVICE v101_DGB TRUE FALSE

在這個數據庫中已經啟用了三個不同的跟蹤狀態

1.第一行記錄顯示將會對在SQL*Plus中執行的所有sql語句進行跟蹤

2.第二行記錄顯示將會對帶有客戶端標識符"HUGO'的所有會話進行跟蹤

3.第三行記錄顯示將會對使用服務"v101_DGB'連接到數據庫的所有程序進行跟蹤

session_trace_enable函數

可以使用session_trace_enable過程來對本地實例的一個指定的數據庫會話啟用sql跟蹤.

語法如下:

啟用sql跟蹤

dbms_monitor.session_trace_enable(session_id => x, serial_num => y,

waits=>(TRUE|FALSE),binds=>(TRUE|FALSE) );

禁止sql跟蹤

dbms_monitor.session_trace_disable(session_id => x, serial_num => y);

其中waits的缺省值是true,binds的缺省值是false.

可以從v$session視圖中查詢會話id和序列號

SQL> select serial#, sid , username from v$session;

SERIAL# SID USERNAME

------- ----- --------------

1 131

18 139

3 140

11 143 SCOTT

然后可以使用下面的命令來對指定的會話啟用跟蹤

SQL> execute dbms_monitor.session_trace_enable(143,11);

跟蹤狀態在數據庫重啟后就會被刪除可以查詢dba_enabled_traces視圖看到沒有記錄

sys@JINGYONG> oradebug tracefile_name

/u01/app/oracle/diag/rdbms/jingyong/jingyong/trace/jingyong_ora_2529.trc

sys@JINGYONG> select trace_type,primary_id,qualifier_id1,waits,binds

2 from dba_enabled_traces;

未選定行

當會話斷開或者使用下面的命令可以禁止跟蹤

SQL> execute dbms_monitor.session_trace_disable(143,11);

client_id_trace_enable函數

在多層架構環境中,一個請求從一個終端客戶端通過中間層分發到不同的數據庫會話.這意味著終端客戶端與數據庫會話的聯系不是靜態的.在oracle10g之前沒有方法可以對一個客戶端跨不同數據庫會話進行跟蹤.端到端的跟蹤可以通過一個新的屬性client_identifier來標識它是唯一標識一個特定的終端客戶端.這個客戶端標識符對應于v$session視圖中的client_identifier列.通過系統上下文也可以查看.

語法如下:

啟用跟蹤

execute dbms_monitor.client_id_trace_enable ( client_id =>'client x',

waits => (TRUE|FALSE), binds => (TRUE|FALSE) );

禁止跟蹤

execute dbms_monitor.client_id_trace_disable ( client_id =>'client x');

其中waits的缺省值是true,binds的缺省值是false.

例如:

可以使用dbms_session.set_identifier函數來設置client_identifier

sys@JINGYONG> exec dbms_session.set_identifier('JY');

PL/SQL 過程已成功完成。

sys@JINGYONG> select sys_context('USERENV','CLIENT_IDENTIFIER') client_id from dual;

sys@JINGYONG> select client_identifier client_id from v$session where sid=30;

sys@JINGYONG> exec dbms_monitor.client_id_trace_enable('JY');

PL/SQL 過程已成功完成。

使用查詢來檢查跟蹤是否已經啟用

sys@JINGYONG> select primary_id,qualifier_id1,waits,binds

2 from dba_enabled_traces where trace_type='CLIENT_ID';

PRIMARY_ID QUALIFIER_ID1 WAITS BINDS

---------------- -------------- -------- --------

JY TRUE FALSE

這個跟蹤在數據庫重啟之后還是有效的你得調用函數來禁用.

sys@JINGYONG> exec dbms_monitor.client_id_trace_disable('JY');

PL/SQL 過程已成功完成。

檢查生成的跟文件

Trace file /u01/app/oracle/diag/rdbms/jingyong/jingyong/trace/jingyong_ora_2529.trc

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

ORACLE_HOME = /u01/app/oracle/product/11.2.0/db

System name:Linux

Node name:jingyong

Release:2.6.18-164.el5

Version:#1 SMP Tue Aug 18 15:51:54 EDT 2009

Machine:i686

Instance name: jingyong

Redo thread mounted by this instance: 1

Oracle process number: 21

Unix process pid: 2529, image: oracle@jingyong

*** 2013-11-11 11:31:56.737

*** SESSION ID:(30.32) 2013-11-11 11:31:56.737

*** CLIENT ID:() 2013-11-11 11:31:56.737

*** SERVICE NAME:(jingyong) 2013-11-11 11:31:56.737

*** MODULE NAME:(sqlplus.exe) 2013-11-11 11:31:56.737

*** ACTION NAME:() 2013-11-11 11:31:56.737

PARSING IN CURSOR #8 len=96 dep=0 uid=0 oct=3 lid=0 tim=1384150635839986 hv=3018843459 ad='275fa5ec' sqlid='3gg23wktyzta3'

select primary_id,qualifier_id1,waits,binds

from dba_enabled_traces where trace_type='CLIENT_ID'

END OF STMT

在啟用跟蹤后執行的語句被記錄到了跟蹤文件中.

sys@JINGYONG> select primary_id,qualifier_id1,waits,binds

2 from dba_enabled_traces where trace_type='CLIENT_ID';

未選定行

當你使用MTS時有時將會生成多個跟蹤文件,不同的共享服務器進程能執行sql語句這就將會生成多個跟蹤文件.對于RAC

環境也是一樣.

serv_mod_act_trace_enable函數

端到端跟蹤對于使用MODULE,ACTION,SERVICES標識的應用程序能夠進行有效地管理和計算其工作量.service名,module和

action名提供了一種方法來識別一個應用程序中重要的事務.

你可以使用serv_act_trace_enable過程來對由一組service,module和action名指定的全局會話啟用sql跟蹤,除非指定了特定

的實例名.對于一個會話的service名,module名與v$session視圖中的service_name和module列相對應.

語句如下:

啟用跟蹤

execute dbms_monitor.serv_mod_act_trace_enable('Service S', 'Module M', 'Action A',

waits => (TRUE|FALSE), binds => (TRUE|FALSE), instance_name => 'ORCL' );

禁止跟蹤

execute dbms_monitor.serv_mod_act_trace_disable('Service S', 'Module M', 'Action A');

其中waits的缺省值是true,binds的缺省值是false,instance_name的缺省值是null.

例如想要對在數據庫服務器使用SQL*Plus執行的所有sql語句進行跟蹤可以執行以下命令:

sys@JINGYONG> select module,service_name from v$session where sid=25;

MODULE SERVICE_NAME

----------------------------- ---------------------

sqlplus@jingyong (TNS V1-V3) SYS$USERS

sys@JINGYONG> exec dbms_monitor.serv_mod_act_trace_enable('SYS$USERS','sqlplus@j

ingyong (TNS V1-V3)');

PL/SQL 過程已成功完成。

sys@JINGYONG> select primary_id,qualifier_id1,waits,binds

2 from dba_enabled_traces

3 where trace_type='SERVICE_MODULE';

PRIMARY_ID QUALIFIER_ID1 WAITS BINDS

--------------- ------------------- -------- --------

SYS$USERS sqlplus@jingyong (TNS V1-V3) TRUE FALSE

啟用跟蹤后我們執行一個測試語句

SQL> select 'x' from dual;

檢查生成的跟蹤文件名

SQL> select * from v$diag_info where name='Default Trace File';

INST_ID NAME

---------- ----------------------------------------------------------------

VALUE

--------------------------------------------------------------------------------

1 Default Trace File

/u01/app/oracle/diag/rdbms/jingyong/jingyong/trace/jingyong_ora_4411.trc

查看跟蹤內容如下

trace file /u01/app/oracle/diag/rdbms/jingyong/jingyong/trace/jingyong_ora_4411.trc

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

ORACLE_HOME = /u01/app/oracle/product/11.2.0/db

System name:Linux

Node name:jingyong

Release:2.6.18-164.el5

Version:#1 SMP Tue Aug 18 15:51:54 EDT 2009

Machine:i686

Instance name: jingyong

Redo thread mounted by this instance: 1

Oracle process number: 24

Unix process pid: 4411, image: oracle@jingyong (TNS V1-V3)

*** 2013-11-11 14:34:00.971

*** SESSION ID:(25.412) 2013-11-11 14:34:00.972

*** CLIENT ID:() 2013-11-11 14:34:00.972

*** SERVICE NAME:(SYS$USERS) 2013-11-11 14:34:00.972

*** MODULE NAME:(sqlplus@jingyong (TNS V1-V3)) 2013-11-11 14:34:00.972

*** ACTION NAME:() 2013-11-11 14:34:00.972

WAIT #1: nam='SQL*Net message from client' ela= 152965072 driver id=1650815232 #bytes=1 p3=0 obj#=-1 tim=1384151640937525

CLOSE #1:c=1000,e=521,dep=0,type=0,tim=1384151640973430

=====================

PARSING IN CURSOR #1 len=20 dep=0 uid=0 oct=3 lid=0 tim=1384151640977682 hv=2740543121 ad='275fa9e4' sqlid='04vfkrajpkrnj'

select 'x' from dual

我們執行的測試語句被記錄了在跟蹤文件中.

sys@JINGYONG> exec dbms_monitor.serv_mod_act_trace_disable('SYS$USERS','sqlplus@

jingyong (TNS V1-V3)');

PL/SQL 過程已成功完成。

sys@JINGYONG> select primary_id,qualifier_id1,waits,binds

2 from dba_enabled_traces

3 where trace_type='SERVICE_MODULE';

未選定行

使用trcsess來合并跟蹤文件

從某些跟蹤操作中會得到多個跟蹤文件.在oracle10g之前的版本中你得手動將這些跟蹤文件合并到一起.現在可以使用trcsess工具來幫你合并這些跟蹤文件.

語句如下:

trcsess [output=] [session=] [clientid=] [service=] [action=] [module=]

output=?output destination default being standard output.

session= session to be traced.

Session id is a combination of session Index & session serial number e.g. 8.13.

clientid= clientid to be traced.

service= service to be traced.

action= action to be traced.

module= module to be traced.

Space separated list of trace files with wild card '*' suppor

ted.

[oracle@jingyong trace]$ trcsess output=jingyong_ora_88888888.trc service=jingyong jingyong_ora_2529.trc jingyong_ora_4411.trc

[oracle@jingyong trace]$ ls -lrt jingyong_ora_88888888.trc

-rw-r--r-- 1 oracle oinstall 16219 Nov 11 14:59 jingyong_ora_88888888.trc

dbms_application_info

可以在過程開始一個事務之前使用dbms_application_info.set*過程來注冊一個事務名/客戶端信息/模塊名為以后檢查性能來使用.你應該對以后可能消耗你最多系統資源的活動事務進行指定.

dbms_application_info包有以下過程

SET_CLIENT_INFO ( client_info IN VARCHAR2 );

SET_ACTION ( action_name IN VARCHAR2 );

SET_MODULE ( module_name IN VARCHAR2, action_name IN VARCHAR2 );

例如

sys@JINGYONG> create table emp as select * from scott.emp where 1=0;

表已創建。

sys@JINGYONG> exec dbms_application_info.set_module(module_name=>'add_emp',actio

n_name=>'insert into emp');

PL/SQL 過程已成功完成。

sys@JINGYONG> insert into emp select * from scott.emp;

已創建14行。

sys@JINGYONG> commit;

提交完成。

sys@JINGYONG> exec dbms_application_info.set_module(null,null);

PL/SQL 過程已成功完成。

下面查詢v$sqlarea視圖使用module和action列進行查詢

sys@JINGYONG> select sql_text from v$sqlarea where module='add_emp';

insert into emp select * from scott.emp

sys@JINGYONG> select sql_text from v$sqlarea where action='insert into emp';

insert into emp select * from scott.emp

declare

l_client varchar2(100);

l_mod_name varchar2(100);

l_act_name varchar2(100);

begin

dbms_application_info.read_client_info(l_client);

dbms_application_info.read_module(l_mod_name,l_act_name);

dbms_output.put_line(l_client);

dbms_output.put_line(l_mod_name);

end;

dbms_session包：只能跟蹤當前會話，不能指定會話。

跟蹤當前會話：

SQL> exec dbms_session.set_sql_trace(true);

SQL> 執行sql

SQL> exec dbms_session.set_sql_trace(false);

dbms_session.set_sql_trace相當于alter session set sql_trace，從生成的trace文件可以明確地看alter session set sql_trace語句。

使用dbms_session.session_trace_enable過程，不僅可以看到等待事件信息還可以看到綁定變量信息，相當于alter session set events '10046 trace name context forever, level 12';語句，從生成的trace文件可以確認。

SQL> exec dbms_session.session_trace_enable(waits=>true,binds=>true);

SQL> 執行sql

SQL> exec dbms_session.session_trace_enable(); --This procedure resets the session-level SQL trace for the session from which it was called.

dbms_support包：不應該使用這種方法，非官方支持。

系統默認沒有安裝這個包，可以手動執行$ORACLE_HOME/rdbms/admin/bmssupp.sql腳本來創建該包。

SQL> desc dbms_support

FUNCTION MYSID RETURNS NUMBER

FUNCTION PACKAGE_VERSION RETURNS VARCHAR2

PROCEDURE START_TRACE

Argument Name Type In/Out Default?

------------------------------ ----------------------- ------ --------

WAITS BOOLEAN IN DEFAULT

BINDS BOOLEAN IN DEFAULT

PROCEDURE START_TRACE_IN_SESSION

Argument Name Type In/Out Default?

------------------------------ ----------------------- ------ --------

SID NUMBER IN

SERIAL NUMBER IN

WAITS BOOLEAN IN DEFAULT

BINDS BOOLEAN IN DEFAULT

PROCEDURE STOP_TRACE

PROCEDURE STOP_TRACE_IN_SESSION

Argument Name Type In/Out Default?

------------------------------ ----------------------- ------ --------

SID NUMBER IN

SERIAL NUMBER IN

SQL> select dbms_support.package_version from dual;

PACKAGE_VERSION

--------------------------------------------------------------------------------

DBMS_SUPPORT Version 1.0 (17-Aug-1998) - Requires Oracle 7.2 - 8.0.5

SQL> select dbms_support.mysid from dual;

MYSID

----------

292

SQL> select * from v$mystat where rownum=1;

SID STATISTIC# VALUE

---------- ---------- ----------

292 0 1

跟蹤當前會話：

SQL> exec dbms_support.start_trace

SQL> 執行sql

SQL> exec dbms_support.stop_trace

跟蹤其他會話：等待事件+綁定變量，相當于level 12的10046事件。

SQL> select sid,serial#,username from v$session where ...;

SQL> exec dbms_support.start_trace_in_session(sid=>sid,serial=>serial#,waits=>true,binds=>true);

SQL> exec dbms_support.stop_trace_in_session(sid=>sid,serial=>serial#);

dbms_system包：9i時使用

跟蹤其他會話：

SQL> select sid,serial#,username from v$session where ...;

SQL> exec dbms_system.set_sql_trace_in_session(sid,serial#,true);

可以等候片刻，跟蹤session執行任務,捕獲sql操作…

SQL> exec dbms_system.set_sql_trace_in_session(sid,serial#,false);

ps：dbms_system這個包在10gR2官方文檔上面沒有找到這個包的說明，但數據庫中有。

SQL> exec sys.dbms_system.SET_BOOL_PARAM_IN_SESSION(sid, serial#, 'sql_trace', TRUE);

SQL> exec sys.dbms_system.SET_BOOL_PARAM_IN_SESSION(sid, serial#, 'sql_trace', FALSE);

使用dbms_system.set_ev設置10046事件

SQL> select sid,serial#,username from v$session where ...;

SQL> exec dbms_system.set_ev(sid,serial#,10046,12,'');

SQL> exec dbms_system.set_ev(sid,serial#,10046,0,'');

最后一個參數只有為''時，才會生成trace文件，否則不報錯，但沒有trace文件生成。

3.數據庫hang住是一個特定會話出現hang住還是幾個會話出現hang住還是所有的會話都出現hang住

如果數據庫是一個會話或幾個會話出現hang住可以對這個會話執行10046跟蹤,可以對這個會話收集一些errorstacks信息,也可以當問題出現時生成一個awr或statspack報告

生成轉儲和errorstack信息的方法如下:

為了轉儲跟蹤和errorstacks信息,可以使用操作系統進程ID或者oracle進程ID.比如可以通過oracle的sid來查詢到操作系統進ID:

SELECT p.pid, p.SPID,s.SID

FROM v$process p, v$session s

WHERE s.paddr = p.addr

AND s.SID = &SID;

SPID是操作系統標識符

SID是oracle會話標識符

PID是oracle進程標識符

比如一個SPID是1254,pid是56如果使用SPID來生成轉儲和errorstacks信息可以執行下面的語句:

connect / as sysdba

ALTER SESSION SET tracefile_identifier = 'STACK_10046';

oradebug setospid 1254

oradebug unlimit

oradebug event 10046 trace name context forever,level 12

oradebug dump errorstack 3

oradebug tracefile_name

oradebug event 10046 trace name context off

如果使用PID來生成轉儲和errorstacks信息可以執行下面的語句:

connect / as sysdba

ALTER SESSION SET tracefile_identifier = 'STACK_10046';

oradebug setpid 56

oradebug unlimit

oradebug event 10046 trace name context forever,level 12

oradebug dump errorstack 3

oradebug tracefile_name

oradebug event 10046 trace name context off

其中oradebug tracefile_name命令會顯示跟蹤文件的名字和位置,在生成的跟蹤文件名字會包含STACK_10046字符

如果要對當前會話收集errorstacks信息首先要找出當前會話的SPID或PID可以執行如下語句來獲得:

SELECT p.pid, p.SPID,s.SID

FROM v$process p, v$session s

WHERE s.paddr = p.addr

AND s.audsid = userenv('SESSIONID') ;

或者

SELECT p.pid, p.SPID,s.SID

FROM v$process p,v$session s

WHERE s.paddr = p.addr

AND s.SID =

(SELECT DISTINCT SID

FROM V$MYSTAT);

如果數據庫是所有會話出現hang也就是整個數據庫出現hang住了診斷hang住的方法如下:

當一個數據庫出現Hang的問題時從數據庫中收集信息來診斷掛志的根本原因是非常有用的.數據庫Hang的原因往往是孤立的可以使用收集來的診斷信息來解決.另外如果不能解決可以用獲得的信息來避免這個問題的再次重現.

解決方法

診斷數據庫Hang需要什么信息

數據庫Hang的特點是一些進程正在等待另一些進程的完成.通常有一個或多個阻塞進程被困或者正在努力工作但不是迅速的釋放資源.為了診斷需要以下信息:

1.Hanganalyze and Systemstate Dumps

2.數據庫性能的awr/statspack快照

3.及時的RDA

Hanganalyze and Systemstate Dumps

Hang分析和系統狀態轉儲提供了在一個特定時間點的數據庫中的進程信息.Hang分析提供了在Hang鏈表中所有進程的信息,系統狀態提供了數據庫中所有進程的信息.當查看一個潛在的Hang情況時你需要判斷是否一個進程被因或動行緩慢.通過在兩個連續的時間間隔內收集這些轉儲信息如果進程被困這些跟蹤信息可以用于將來的診斷可能幫助你提供一些解決方法.Hang分析用來總結和確認數據庫是真的Hang還是只是緩慢并提供了一致性快照,系統狀態轉儲顯示了數據庫中每一個進程正在做什么

收集Hang分析和系統狀態轉儲信息

登錄系統

使用sql*plus以sysdba身份來登錄

sqlplus '/ as sysdba'

如果連接時出現問題在oracle10gr2中可以使用sqlplus的"preliminary connection'

sqlplus -prelim '/ as sysdba'

注意:從oracle 11.2.0.2開始Hang分析在sqlplus的'preliminary connection'連接下將不會生成輸出因為它要會請求一個進程的狀態對象和一個會話狀態對象.如果正試圖分析跟蹤會輸出:

HANG ANALYSIS:

ERROR: Can not perform hang analysis dump without a process state object and a session state object.

( process=(nil), sess=(nil) )

非rac環境收集Hang分析和系統狀態的收集命令

有些時候數據庫可能只是非常的慢而不是真正的Hang.因此建議收集級別為2的Hang分析和系統狀態轉儲來判斷這些進程是正在執行還是已經停止執行

持起分析

sqlplus '/ as sysdba'

oradebug setmypid

oradebug unlimit

oradebug hanganalyze 3

-- Wait one minute before getting the second hanganalyze

oradebug hanganalyze 3

oradebug tracefile_name

exit

系統轉儲

sqlplus '/ as sysdba'

oradebug setmypid

oradebug unlimit

oradebug dump systemstate 266

oradebug tracefile_name

exit

rac環境收集Hang分析和系統狀態的收集命令

如果在你的系統中沒有應用相關的補丁程序使用級別為266或267的系統狀態轉儲會有2個bug.因此在沒有應用這些補丁收集這些級別的轉儲是不明智的選擇

補丁信息如下:

Document 11800959.8 Bug 11800959 - A SYSTEMSTATE dump with level >= 10 in RAC dumps huge BUSY GLOBAL CACHE ELEMENTS - can hang/crash instances

Document 11827088.8 Bug 11827088 - Latch 'gc element' contention, LMHB terminates the instance

在修正bug 11800959和bug 11827088的情況下對于rac環境懼訂Hang分析和系統狀態的收集命令如下:

sqlplus '/ as sysdba'

oradebug setorapname reco

oradebug unlimit

oradebug -g all hanganalyze 3

oradebug -g all dump systemstate 266

exit

在沒有修正bug 11800959和bug 11827088的情況下對于rac環境懼訂Hang分析和系統狀態的收集命令如下:

sqlplus '/ as sysdba'

oradebug setorapname reco

oradebug unlimit

oradebug -g all hanganalyze 3

oradebug -g all dump systemstate 258

exit

在rac環境中會在每一個實例的跟蹤文件中創建所有實例的轉儲信息

對Hang分析和系統狀態轉儲的級別說明

Hang分析級別

level 3(級別3):在oracle11g之前level 3對Hang鏈表中的相關進程也會收集一個簡短的堆棧信息

系統狀態轉儲級別

level 258(級別258)是一個快速的選擇但是會丟失一些鎖的元數據信息

level 267(級別267)它包含了理解成本所需要的額外的緩沖區緩存/鎖元數據信息

其它的方法

如果不能連接到系統時如何收集系統狀態轉儲信息

通常有兩種方法來在系統Hang不能連接時來生成系統狀態轉儲信息

1.alter session set events 'immediate trace name SYSTEMSTATE level 10';

2.$ sqlplus

connect sys/passwd as sysdba

oradebug setospid oradebug unlimit

oradebug dump systemstate 10

(注意:在oradebug中不能使用任何半冒號,如果你的數據庫是比oracle9i還老的版本你將需要使用svrmgrl來連接到內部)

當你使用這兩種方法中的一種時,要確保在兩次轉儲時內部連接斷開.這種方法生成的轉儲將在你的user_dump_dest目錄中是分開的ora_.trc文件

在非常嚴重的情況下不能使用svrmgrl或sqlplus進行連接執行這些必要的命令.在這種情況下仍然有一個后門方法使用調試器比如你的系統有dbx的話可以用dbx來生成系統狀態轉儲信息.被連接到的轉儲核心進程可能會被殺死所以不能連接到一個oracle后臺進程.dbx的語法如下:

dbx -a PID (where PID = any oracle shadow process)

dbx() print ksudss(10)

...return value printed here

dbx() detach

首先你需要找到一個影子進程

(jy) % ps -ef |grep sqlplus

osupport 78526 154096 0 12:11:05 pts/1 0:00 sqlplus scott/tiger

osupport 94130 84332 1 12:11:20 pts/3 0:00 grep sqlplus

(jy) % ps -ef |grep 78526

osupport 28348 78526 0 12:11:05 - 0:00 oracles734 (DESCRIPTION=(LOCAL

osupport 78526 154096 0 12:11:05 pts/1 0:00 sqlplus scott/tiger

osupport 94132 84332 1 12:11:38 pts/3 0:00 grep 78526

這樣將會連接到影子進程PID 28348上.當返回提示符時輸入ksudss(10)命令和detach:

(jy) % dbx -a 28348

Waiting to attach to process 28348 ...

Successfully attached to oracle.

warning: Directory containing oracle could not be determined.

Apply 'use' command to initialize source path.

Type 'help' for help.

reading symbolic information ...

stopped in read at 0xd016fdf0

0xd016fdf0 (read+0x114) 80410014 lwz r2,0x14(r1)

(dbx) print ksudss(10)

(dbx) detach

在user_dump_dest目錄中你將會通過跟蹤的pid找到一個系統狀態轉儲文件

(jy) % ls -lrt *28348*

-rw-r----- 1 osupport dba 46922 Oct 10 12:12 ora_28348.trc

core_28348:

total 72

-rw-r--r-- 1 osupport dba 16567 Oct 10 12:12 core

drwxr-xr-x 7 osupport dba 12288 Oct 10 12:12 ../

drwxr-x--- 2 osupport dba 512 Oct 10 12:12 ./

在跟蹤文件中你將會找到常用的頭信息.在oracle7.3.4并行操作系統中在這后面緊跟的是鎖信息然后才是系統轉儲信息.

在oracle8并行操作系統中和非并行操作系統和oracle7.3.4非并行操作系統的系統狀態信息是緊跟頭信息.

在轉儲文件中頭信息如下:

Dump file /oracle/mpp/734/rdbms/log/ora_28348.trc

Oracle7 Server Release 7.3.4.4.1 - Production

With the distributed, replication, parallel query, Parallel Server

and Spatial Data options

PL/SQL Release 2.3.4.4.1 - Production

ORACLE_HOME = /oracle/mpp/734

System name: AIX

Node name: saki

Release: 3

Version: 4

Machine: 000089914C00

Instance name: s734

Redo thread mounted by this instance: 2

Oracle process number: 0

Unix process pid: 28348, image:

ksinfy: nfytype = 0x5

ksinfy: calling scggra(&se)

scggra: SCG_PROCESS_LOCKING not defined

scggra: calling lk_group_attach()

ksinfy: returning

*** SESSION ID:(12.15) 2000.10.10.12.11.06.000

ksqcmi: get or convert

*** 2000.10.10.12.12.08.000

===================================================

SYSTEM STATE

.....

確保在這個文件中有一個end of system state.可以對它使用grep或在vi中搜索.如果沒有那么這個跟蹤文件是不過完整.

可能是因為init.ora文件中的max_dump_file的大小太小了.

對于oracle10g及以后的版本:

在有些情況下不連接到實例是允許的(在有些ora-20的情況下,對于oracle10.1.x,對于sqlplus有一個新選項來允許訪問實例來生成跟蹤文件)sqlplus -prelim / as sysdba

例如

export ORACLE_SID=PROD ## Replace PROD with the SID you want to trace

sqlplus -prelim / as sysdba

oradebug setmypid

oradebug unlimit;

oradebug dump systemstate 10

在rac系統中,Hang分析,系統轉儲和其它一些rac信息可以使用racdiag.sql腳本來進行收集:

-- NAME: RACDIAG.SQL

-- SYS OR INTERNAL USER, CATPARR.SQL ALREADY RUN, PARALLEL QUERY OPTION ON

-- ------------------------------------------------------------------------

-- AUTHOR:

-- Michael Polaski - Oracle Support Services

-- ------------------------------------------------------------------------

-- PURPOSE:

-- This script is intended to provide a user friendly guide to troubleshoot

-- RAC hung sessions or slow performance scenerios. The script includes

-- information to gather a variety of important debug information to determine

-- the cause of a RAC session level hang. The script will create a file

-- called racdiag_.out in your local directory while dumping hang analyze

-- dumps in the user_dump_dest(s) and background_dump_dest(s) on all nodes.

-- ------------------------------------------------------------------------

-- DISCLAIMER:

-- This script is provided for educational purposes only. It is NOT

-- supported by Oracle World Wide Technical Support.

-- The script has been tested and appears to work as intended.

-- You should always run new scripts on a test instance initially.

-- ------------------------------------------------------------------------

-- Script output is as follows:

set echo off

set feedback off

column timecol new_value timestamp

column spool_extension new_value suffix

select to_char(sysdate,'Mondd_hhmi') timecol,

'.out' spool_extension from sys.dual;

column output new_value dbname

select value || '_' output

from v$parameter where name = 'db_name';

spool racdiag_&&dbname&&timestamp&&suffix

set lines 200

set pagesize 35

set trim on

set trims on

alter session set nls_date_format = 'MON-DD-YYYY HH24:MI:SS';

alter session set timed_statistics = true;

set feedback on

select to_char(sysdate) time from dual;

set numwidth 5

column host_name format a20 tru

select inst_id, instance_name, host_name, version, status, startup_time

from gv$instance

order by inst_id;

set echo on

-- WAIT CHAINS

-- 11.x+ Only (This will not work in < v11

-- See Note 1428210.1 for instructions on interpreting.

set pages 1000

set lines 120

set heading off

column w_proc format a50 tru

column instance format a20 tru

column inst format a28 tru

column wait_event format a50 tru

column p1 format a16 tru

column p2 format a16 tru

column p3 format a15 tru

column Seconds format a50 tru

column sincelw format a50 tru

column blocker_proc format a50 tru

column waiters format a50 tru

column chain_signature format a100 wra

column blocker_chain format a100 wra

SELECT *

FROM (SELECT 'Current Process: '||osid W_PROC, 'SID '||i.instance_name INSTANCE,

'INST #: '||instance INST,'Blocking Process: '||decode(blocker_osid,null,'',blocker_osid)||

' from Instance '||blocker_instance BLOCKER_PROC,'Number of waiters: '||num_waiters waiters,

'Wait Event: ' ||wait_event_text wait_event, 'P1: '||p1 p1, 'P2: '||p2 p2, 'P3: '||p3 p3,

'Seconds in Wait: '||in_wait_secs Seconds, 'Seconds Since Last Wait: '||time_since_last_wait_secs sincelw,

'Wait Chain: '||chain_id ||': '||chain_signature chain_signature,'Blocking Wait Chain: '||decode(blocker_chain_id,null,

'',blocker_chain_id) blocker_chain

FROM v$wait_chains wc,

v$instance i

WHERE wc.instance = i.instance_number (+)

AND ( num_waiters > 0

OR ( blocker_osid IS NOT NULL

AND in_wait_secs > 10 ) )

ORDER BY chain_id,

num_waiters DESC)

WHERE ROWNUM < 101; -- Taking Hang Analyze dumps -- This may take a little while... oradebug setmypid oradebug unlimit oradebug -g all hanganalyze 3 -- This part may take the longest, you can monitor bdump or udump to see if -- the file is being generated. oradebug -g all dump systemstate 258 -- WAITING SESSIONS: -- The entries that are shown at the top are the sessions that have -- waited the longest amount of time that are waiting for non-idle wait -- events (event column). You can research and find out what the wait -- event indicates (along with its parameters) by checking the Oracle -- Server Reference Manual or look for any known issues or documentation -- by searching Metalink for the event name in the search bar. Example -- (include single quotes): [ 'buffer busy due to global cache' ]. -- Metalink and/or the Server Reference Manual should return some useful -- information on each type of wait event. The inst_id column shows the -- instance where the session resides and the SID is the unique identifier -- for the session (gv$session). The p1, p2, and p3 columns will show -- event specific information that may be important to debug the problem. -- To find out what the p1, p2, and p3 indicates see the next section. -- Items with wait_time of anything other than 0 indicate we do not know -- how long these sessions have been waiting. -- set numwidth 15 set heading on column state format a7 tru column event format a25 tru column last_sql format a40 tru select sw.inst_id, sw.sid, sw.state, sw.event, sw.seconds_in_wait seconds, sw.p1, sw.p2, sw.p3, sa.sql_text last_sql from gv$session_wait sw, gv$session s, gv$sqlarea sa where sw.event not in ('rdbms ipc message','smon timer','pmon timer', 'SQL*Net message from client','lock manager wait for remote message', 'ges remote message', 'gcs remote message', 'gcs for action', 'client message', 'pipe get', 'null event', 'PX Idle Wait', 'single-task message', 'PX Deq: Execution Msg', 'KXFQ: kxfqdeq - normal deqeue', 'listen endpoint status','slave wait','wakeup time manager') and sw.seconds_in_wait > 0

and (sw.inst_id = s.inst_id and sw.sid = s.sid)

and (s.inst_id = sa.inst_id and s.sql_address = sa.address)

order by seconds desc;

-- EVENT PARAMETER LOOKUP:

-- This section will give a description of the parameter names of the

-- events seen in the last section. p1test is the parameter value for

-- p1 in the WAITING SESSIONS section while p2text is the parameter

-- value for p3 and p3 text is the parameter value for p3. The

-- parameter values in the first section can be helpful for debugging

-- the wait event.

column event format a30 tru

column p1text format a25 tru

column p2text format a25 tru

column p3text format a25 tru

select distinct event, p1text, p2text, p3text

from gv$session_wait sw

where sw.event not in ('rdbms ipc message','smon timer','pmon timer',

'SQL*Net message from client','lock manager wait for remote message',

'ges remote message', 'gcs remote message', 'gcs for action', 'client message',

'pipe get', 'null event', 'PX Idle Wait', 'single-task message',

'PX Deq: Execution Msg', 'KXFQ: kxfqdeq - normal deqeue',

'listen endpoint status','slave wait','wakeup time manager')

and seconds_in_wait > 0

order by event;

-- GES LOCK BLOCKERS:

-- This section will show us any sessions that are holding locks that

-- are blocking other users. The inst_id will show us the instance that

-- the session resides on while the sid will be a unique identifier for

-- the session. The grant_level will show us how the GES lock is granted to

-- the user. The request_level will show us what status we are trying to

-- obtain. The lockstate column will show us what status the lock is in.

-- The last column shows how long this session has been waiting.

set numwidth 5

column state format a16 tru;

column event format a30 tru;

select dl.inst_id, s.sid, p.spid, dl.resource_name1,

decode(substr(dl.grant_level,1,8),'KJUSERNL','Null','KJUSERCR','Row-S (SS)',

'KJUSERCW','Row-X (SX)','KJUSERPR','Share','KJUSERPW','S/Row-X (SSX)',

'KJUSEREX','Exclusive',request_level) as grant_level,

decode(substr(dl.request_level,1,8),'KJUSERNL','Null','KJUSERCR','Row-S (SS)',

'KJUSERCW','Row-X (SX)','KJUSERPR','Share','KJUSERPW','S/Row-X (SSX)',

'KJUSEREX','Exclusive',request_level) as request_level,

decode(substr(dl.state,1,8),'KJUSERGR','Granted','KJUSEROP','Opening',

'KJUSERCA','Canceling','KJUSERCV','Converting') as state,

s.sid, sw.event, sw.seconds_in_wait sec

from gv$ges_enqueue dl, gv$process p, gv$session s, gv$session_wait sw

where blocker = 1

and (dl.inst_id = p.inst_id and dl.pid = p.spid)

and (p.inst_id = s.inst_id and p.addr = s.paddr)

and (s.inst_id = sw.inst_id and s.sid = sw.sid)

order by sw.seconds_in_wait desc;

-- GES LOCK WAITERS:

-- This section will show us any sessions that are waiting for locks that

-- are blocked by other users. The inst_id will show us the instance that

-- the session resides on while the sid will be a unique identifier for

-- the session. The grant_level will show us how the GES lock is granted to

-- the user. The request_level will show us what status we are trying to

-- obtain. The lockstate column will show us what status the lock is in.

-- The last column shows how long this session has been waiting.

set numwidth 5

column state format a16 tru;

column event format a30 tru;

select dl.inst_id, s.sid, p.spid, dl.resource_name1,

decode(substr(dl.grant_level,1,8),'KJUSERNL','Null','KJUSERCR','Row-S (SS)',

'KJUSERCW','Row-X (SX)','KJUSERPR','Share','KJUSERPW','S/Row-X (SSX)',

'KJUSEREX','Exclusive',request_level) as grant_level,

decode(substr(dl.request_level,1,8),'KJUSERNL','Null','KJUSERCR','Row-S (SS)',

'KJUSERCW','Row-X (SX)','KJUSERPR','Share','KJUSERPW','S/Row-X (SSX)',

'KJUSEREX','Exclusive',request_level) as request_level,

decode(substr(dl.state,1,8),'KJUSERGR','Granted','KJUSEROP','Opening',

'KJUSERCA','Cancelling','KJUSERCV','Converting') as state,

s.sid, sw.event, sw.seconds_in_wait sec

from gv$ges_enqueue dl, gv$process p, gv$session s, gv$session_wait sw

where blocked = 1

and (dl.inst_id = p.inst_id and dl.pid = p.spid)

and (p.inst_id = s.inst_id and p.addr = s.paddr)

and (s.inst_id = sw.inst_id and s.sid = sw.sid)

order by sw.seconds_in_wait desc;

-- LOCAL ENQUEUES:

-- This section will show us if there are any local enqueues. The inst_id will

-- show us the instance that the session resides on while the sid will be a

-- unique identifier for. The addr column will show the lock address. The type

-- will show the lock type. The id1 and id2 columns will show specific

-- parameters for the lock type.

set numwidth 12

column event format a12 tru

select l.inst_id, l.sid, l.addr, l.type, l.id1, l.id2,

decode(l.block,0,'blocked',1,'blocking',2,'global') block,

sw.event, sw.seconds_in_wait sec

from gv$lock l, gv$session_wait sw

where (l.sid = sw.sid and l.inst_id = sw.inst_id)

and l.block in (0,1)

order by l.type, l.inst_id, l.sid;

-- LATCH HOLDERS:

-- If there is latch contention or 'latch free' wait events in the WAITING

-- SESSIONS section we will need to find out which proceseses are holding

-- latches. The inst_id will show us the instance that the session resides

-- on while the sid will be a unique identifier for. The username column

-- will show the session's username. The os_user column will show the os

-- user that the user logged in as. The name column will show us the type

-- of latch being waited on. You can search Metalink for the latch name in

-- the search bar. Example (include single quotes):

-- [ 'library cache' latch ]. Metalink should return some useful information

-- on the type of latch.

set numwidth 5

select distinct lh.inst_id, s.sid, s.username, p.username os_user, lh.name

from gv$latchholder lh, gv$session s, gv$process p

where (lh.sid = s.sid and lh.inst_id = s.inst_id)

and (s.inst_id = p.inst_id and s.paddr = p.addr)

order by lh.inst_id, s.sid;

-- LATCH STATS:

-- This view will show us latches with less than optimal hit ratios

-- The inst_id will show us the instance for the particular latch. The

-- latch_name column will show us the type of latch. You can search Metalink

-- for the latch name in the search bar. Example (include single quotes):

-- [ 'library cache' latch ]. Metalink should return some useful information

-- on the type of latch. The hit_ratio shows the percentage of time we

-- successfully acquired the latch.

column latch_name format a30 tru

select inst_id, name latch_name,

round((gets-misses)/decode(gets,0,1,gets),3) hit_ratio,

round(sleeps/decode(misses,0,1,misses),3) "SLEEPS/MISS"

from gv$latch

where round((gets-misses)/decode(gets,0,1,gets),3) < .99

and gets != 0

order by round((gets-misses)/decode(gets,0,1,gets),3);

-- No Wait Latches:

select inst_id, name latch_name,

round((immediate_gets/(immediate_gets+immediate_misses)), 3) hit_ratio,

round(sleeps/decode(immediate_misses,0,1,immediate_misses),3) "SLEEPS/MISS"

from gv$latch

where round((immediate_gets/(immediate_gets+immediate_misses)), 3) < .99 and immediate_gets + immediate_misses > 0

order by round((immediate_gets/(immediate_gets+immediate_misses)), 3);

-- GLOBAL CACHE CR PERFORMANCE

-- This shows the average latency of a consistent block request.

-- AVG CR BLOCK RECEIVE TIME should typically be about 15 milliseconds

-- depending on your system configuration and volume, is the average

-- latency of a consistent-read request round-trip from the requesting

-- instance to the holding instance and back to the requesting instance. If

-- your CPU has limited idle time and your system typically processes

-- long-running queries, then the latency may be higher. However, it is

-- possible to have an average latency of less than one millisecond with

-- User-mode IPC. Latency can be influenced by a high value for the

-- DB_MULTI_BLOCK_READ_COUNT parameter. This is because a requesting process

-- can issue more than one request for a block depending on the setting of

-- this parameter. Correspondingly, the requesting process may wait longer.

-- Also check interconnect badwidth, OS tcp settings, and OS udp settings if

-- AVG CR BLOCK RECEIVE TIME is high.

set numwidth 20

column "AVG CR BLOCK RECEIVE TIME (ms)" format 9999999.9

select b1.inst_id, b2.value "GCS CR BLOCKS RECEIVED",

b1.value "GCS CR BLOCK RECEIVE TIME",

((b1.value / b2.value) * 10) "AVG CR BLOCK RECEIVE TIME (ms)"

from gv$sysstat b1, gv$sysstat b2

where b1.name = 'global cache cr block receive time' and

b2.name = 'global cache cr blocks received' and b1.inst_id = b2.inst_id

or b1.name = 'gc cr block receive time' and

b2.name = 'gc cr blocks received' and b1.inst_id = b2.inst_id ;

-- GLOBAL CACHE LOCK PERFORMANCE

-- This shows the average global enqueue get time.

-- Typically AVG GLOBAL LOCK GET TIME should be 20-30 milliseconds. the

-- elapsed time for a get includes the allocation and initialization of a

-- new global enqueue. If the average global enqueue get (global cache

-- get time) or average global enqueue conversion times are excessive,

-- then your system may be experiencing timeouts. See the 'WAITING SESSIONS',

-- 'GES LOCK BLOCKERS', GES LOCK WAITERS', and 'TOP 10 WAIT EVENTS ON SYSTEM'

-- sections if the AVG GLOBAL LOCK GET TIME is high.

set numwidth 20

column "AVG GLOBAL LOCK GET TIME (ms)" format 9999999.9

select b1.inst_id, (b1.value + b2.value) "GLOBAL LOCK GETS",

b3.value "GLOBAL LOCK GET TIME",

(b3.value / (b1.value + b2.value) * 10) "AVG GLOBAL LOCK GET TIME (ms)"

from gv$sysstat b1, gv$sysstat b2, gv$sysstat b3

where b1.name = 'global lock sync gets' and

b2.name = 'global lock async gets' and b3.name = 'global lock get time'

and b1.inst_id = b2.inst_id and b2.inst_id = b3.inst_id

or b1.name = 'global enqueue gets sync' and

b2.name = 'global enqueue gets async' and b3.name = 'global enqueue get time'

and b1.inst_id = b2.inst_id and b2.inst_id = b3.inst_id;

-- RESOURCE USAGE

-- This section will show how much of our resources we have used.

set numwidth 8

select inst_id, resource_name, current_utilization, max_utilization,

initial_allocation

from gv$resource_limit

where max_utilization > 0

order by inst_id, resource_name;

-- DLM TRAFFIC INFORMATION

-- This section shows how many tickets are available in the DLM. If the

-- TCKT_WAIT columns says "YES" then we have run out of DLM tickets which

-- could cause a DLM hang. Make sure that you also have enough TCKT_AVAIL.

set numwidth 10

select * from gv$dlm_traffic_controller

order by TCKT_AVAIL;

-- DLM MISC

set numwidth 10

select * from gv$dlm_misc;

-- LOCK CONVERSION DETAIL:

-- This view shows the types of lock conversion being done on each instance.

select * from gv$lock_activity;

-- INITIALIZATION PARAMETERS:

-- Non-default init parameters for each node.

set numwidth 5

column name format a30 tru

column value format a50 wra

column description format a60 tru

select inst_id, name, value, description

from gv$parameter

where isdefault = 'FALSE'

order by inst_id, name;

-- TOP 10 WAIT EVENTS ON SYSTEM

-- This view will provide a summary of the top wait events in the db.

set numwidth 10

column event format a25 tru

select inst_id, event, time_waited, total_waits, total_timeouts

from (select inst_id, event, time_waited, total_waits, total_timeouts

from gv$system_event where event not in ('rdbms ipc message','smon timer',

'pmon timer', 'SQL*Net message from client','lock manager wait for remote message',

'ges remote message', 'gcs remote message', 'gcs for action', 'client message',

'pipe get', 'null event', 'PX Idle Wait', 'single-task message',

'PX Deq: Execution Msg', 'KXFQ: kxfqdeq - normal deqeue',

'listen endpoint status','slave wait','wakeup time manager')

order by time_waited desc)

where rownum < 11 order by time_waited desc; -- SESSION/PROCESS REFERENCE: -- This section is very important for most of the above sections to find out -- which user/os_user/process is identified to which session/process. -- set numwidth 7 column event format a30 tru column program format a25 tru column username format a15 tru select p.inst_id, s.sid, s.serial#, p.pid, p.spid, p.program, s.username, p.username os_user, sw.event, sw.seconds_in_wait sec from gv$process p, gv$session s, gv$session_wait sw where (p.inst_id = s.inst_id and p.addr = s.paddr) and (s.inst_id = sw.inst_id and s.sid = sw.sid) order by p.inst_id, s.sid; -- SYSTEM STATISTICS: -- All System Stats with values of > 0. These can be referenced in the

-- Server Reference Manual

set numwidth 5

column name format a60 tru

column value format 9999999999999999999999999

select inst_id, name, value

from gv$sysstat

where value > 0

order by inst_id, name;

-- CURRENT SQL FOR WAITING SESSIONS:

-- Current SQL for any session in the WAITING SESSIONS list

set numwidth 5

column sql format a80 wra

select sw.inst_id, sw.sid, sw.seconds_in_wait sec, sa.sql_text sql

from gv$session_wait sw, gv$session s, gv$sqlarea sa

where sw.sid = s.sid (+)

and sw.inst_id = s.inst_id (+)

and s.sql_address = sa.address

and sw.event not in ('rdbms ipc message','smon timer','pmon timer',

'SQL*Net message from client','lock manager wait for remote message',

'ges remote message', 'gcs remote message', 'gcs for action', 'client message',

'pipe get', 'null event', 'PX Idle Wait', 'single-task message',

'PX Deq: Execution Msg', 'KXFQ: kxfqdeq - normal deqeue',

'listen endpoint status','slave wait','wakeup time manager')

and sw.seconds_in_wait > 0

order by sw.seconds_in_wait desc;

-- WAIT CHAINS

-- 11.x+ Only (This will not work in < v11

-- See Note 1428210.1 for instructions on interpreting.

set pages 1000

set lines 120

set heading off

column w_proc format a50 tru

column instance format a20 tru

column inst format a28 tru

column wait_event format a50 tru

column p1 format a16 tru

column p2 format a16 tru

column p3 format a15 tru

column seconds format a50 tru

column sincelw format a50 tru

column blocker_proc format a50 tru

column waiters format a50 tru

column chain_signature format a100 wra

column blocker_chain format a100 wra

SELECT *

FROM (SELECT 'Current Process: '||osid W_PROC, 'SID '||i.instance_name INSTANCE,

'INST #: '||instance INST,'Blocking Process: '||decode(blocker_osid,null,'',blocker_osid)||

' from Instance '||blocker_instance BLOCKER_PROC,'Number of waiters: '||num_waiters waiters,

'Wait Event: ' ||wait_event_text wait_event, 'P1: '||p1 p1, 'P2: '||p2 p2, 'P3: '||p3 p3,

'Seconds in Wait: '||in_wait_secs Seconds, 'Seconds Since Last Wait: '||time_since_last_wait_secs sincelw,

'Wait Chain: '||chain_id ||': '||chain_signature chain_signature,'Blocking Wait Chain: '||decode(blocker_chain_id,null,

'',blocker_chain_id) blocker_chain

FROM v$wait_chains wc,

v$instance i

WHERE wc.instance = i.instance_number (+)

AND ( num_waiters > 0

OR ( blocker_osid IS NOT NULL

AND in_wait_secs > 10 ) )

ORDER BY chain_id,

num_waiters DESC)

WHERE ROWNUM < 101;

-- Taking Hang Analyze dumps

-- This may take a little while...

oradebug setmypid

oradebug unlimit

oradebug -g all hanganalyze 3

-- This part may take the longest, you can monitor bdump or udump to see

-- if the file is being generated.

oradebug -g all dump systemstate 258

set echo off

select to_char(sysdate) time from dual;

spool off

-- ---------------------------------------------------------------------------

Prompt;

Prompt racdiag output files have been written to:;

Prompt;

host pwd

Prompt alert log and trace files are located in:;

column host_name format a12 tru

column name format a20 tru

column value format a60 tru

select distinct i.host_name, p.name, p.value

from gv$instance i, gv$parameter p

where p.inst_id = i.inst_id (+)

and p.name like '%_dump_dest'

and p.name != 'core_dump_dest';

v$wait_chains

從oracle11gr1開始,dia0后臺進程開始收集Hang分析信息并存儲在內存中的"hang analysis cache"中.它會每3秒鐘收集一次本地的Hang分析和第10秒鐘收集一次全局(rac)Hang分析信息.這些信息在出現Hang時提供快速查看Hang鏈表的方法.

存儲在"hang analysiz cache"中的數據對于診斷數據庫競爭和Hang是非常有效的

有許多數據庫功能可以利用Hang分析緩存:Hang Management, Resource Manager Idle Blocker Kill,

SQL Tune Hang Avoidance和PMON清除以及外部工具象Procwatcher

下面是oracle11gr2中v$wait_chains視圖的描述:

SQL> desc v$wait_chains

Name Null Type

----------------------------------------- -------- ----------------------

CHAIN_ID NUMBER

CHAIN_IS_CYCLE VARCHAR2(5)

CHAIN_SIGNATURE VARCHAR2(801)

CHAIN_SIGNATURE_HASH NUMBER

INSTANCE NUMBER

OSID VARCHAR2(25)

PID NUMBER

SID NUMBER

SESS_SERIAL# NUMBER

BLOCKER_IS_VALID VARCHAR2(5)

BLOCKER_INSTANCE NUMBER

BLOCKER_OSID VARCHAR2(25)

BLOCKER_PID NUMBER

BLOCKER_SID NUMBER

BLOCKER_SESS_SERIAL# NUMBER

BLOCKER_CHAIN_ID NUMBER

IN_WAIT VARCHAR2(5)

TIME_SINCE_LAST_WAIT_SECS NUMBER

WAIT_ID NUMBER

WAIT_EVENT NUMBER

WAIT_EVENT_TEXT VARCHAR2(64)

P1 NUMBER

P1_TEXT VARCHAR2(64)

P2 NUMBER

P2_TEXT VARCHAR2(64)

P3 NUMBER

P3_TEXT VARCHAR2(64)

IN_WAIT_SECS NUMBER

TIME_REMAINING_SECS NUMBER

NUM_WAITERS NUMBER

ROW_WAIT_OBJ# NUMBER

ROW_WAIT_FILE# NUMBER

ROW_WAIT_BLOCK# NUMBER

ROW_WAIT_ROW# NUMBER

注意:v$wait_chains等價于gv$視圖可能在rac環境中報告多個實例

使用sql來查詢基本信息

SQL> SELECT chain_id, num_waiters, in_wait_secs, osid, blocker_osid, substr(wait_event_text,1,30)

FROM v$wait_chains; 2

CHAIN_ID NUM_WAITERS IN_WAIT_SECS OSID BLOCKER_OSID SUBSTR(WAIT_EVENT_TEXT,1,30)

---------- ----------- ------------ -------------- ------------------------- -----------------------------

1 0 10198 21045 21044 enq: TX - row lock contention

1 1 10214 21044 SQL*Net message from client

查詢top 100 wait chain processs

set pages 1000

set lines 120

set heading off

column w_proc format a50 tru

column instance format a20 tru

column inst format a28 tru

column wait_event format a50 tru

column p1 format a16 tru

column p2 format a16 tru

column p3 format a15 tru

column Seconds format a50 tru

column sincelw format a50 tru

column blocker_proc format a50 tru

column waiters format a50 tru

column chain_signature format a100 wra

column blocker_chain format a100 wra

SELECT *

FROM (SELECT 'Current Process: '||osid W_PROC, 'SID '||i.instance_name INSTANCE,

'INST #: '||instance INST,'Blocking Process: '||decode(blocker_osid,null,'',blocker_osid)||

' from Instance '||blocker_instance BLOCKER_PROC,'Number of waiters: '||num_waiters waiters,

'Wait Event: ' ||wait_event_text wait_event, 'P1: '||p1 p1, 'P2: '||p2 p2, 'P3: '||p3 p3,

'Seconds in Wait: '||in_wait_secs Seconds, 'Seconds Since Last Wait: '||time_since_last_wait_secs sincelw,

'Wait Chain: '||chain_id ||': '||chain_signature chain_signature,'Blocking Wait Chain: '||decode(blocker_chain_id,null,

'',blocker_chain_id) blocker_chain

FROM v$wait_chains wc,

v$instance i

WHERE wc.instance = i.instance_number (+)

AND ( num_waiters > 0

OR ( blocker_osid IS NOT NULL

AND in_wait_secs > 10 ) )

ORDER BY chain_id,

num_waiters DESC)

WHERE ROWNUM < 101;

Current Process:21549 SID RAC1 INST #: 1

Blocking Process: from Instance Number of waiters:1

Wait Event:SQL*Net message from client P1: 1650815232 P2: 1 P3:0

Seconds in Wait:36 Seconds Since Last Wait:

Wait Chaing:1 : 'SQL*Net message from client '< ='enq: TX - row lock contention'

Blocking Wait Chain:

Current Process:25627 SID RAC1 INST #: 1

Blocking Process:21549 from Instance 1 Number of waiters:0

Wait Event:enq: TX - row lock contention P1:1415053318 P2: 524316 P3:50784

Seconds in Wait:22 Seconds Since Last Wait:

Wait Chain:1 : 'SQL*Net message from client '< ='enq: TX - row lock contention'

Blocking Wait Chain:

ospid 25627正等待一個TX lock正被ospid 21549所阻塞

ospid 21549正空閑等待'SQL*Net message from client'

在oracle11gr2中的最終阻塞會話

在oracle11gr2中可能將v$session.final_blocking_session看作是最終的阻塞者.最終的阻會話/進程在top等待鏈表上.

這些會話/進程可能是造成問題的原因.

set pages 1000

set lines 120

set heading off

column w_proc format a50 tru

column instance format a20 tru

column inst format a28 tru

column wait_event format a50 tru

column p1 format a16 tru

column p2 format a16 tru

column p3 format a15 tru

column Seconds format a50 tru

column sincelw format a50 tru

column blocker_proc format a50 tru

column fblocker_proc format a50 tru

column waiters format a50 tru

column chain_signature format a100 wra

column blocker_chain format a100 wra

SELECT *

FROM (SELECT 'Current Process: '||osid W_PROC, 'SID '||i.instance_name INSTANCE,

'INST #: '||instance INST,'Blocking Process: '||decode(blocker_osid,null,'',blocker_osid)||

' from Instance '||blocker_instance BLOCKER_PROC,

'Number of waiters: '||num_waiters waiters,

'Final Blocking Process: '||decode(p.spid,null,'',

p.spid)||' from Instance '||s.final_blocking_instance FBLOCKER_PROC,

'Program: '||p.program image,

'Wait Event: ' ||wait_event_text wait_event, 'P1: '||wc.p1 p1, 'P2: '||wc.p2 p2, 'P3: '||wc.p3 p3,

'Seconds in Wait: '||in_wait_secs Seconds, 'Seconds Since Last Wait: '||time_since_last_wait_secs sincelw,

'Wait Chain: '||chain_id ||': '||chain_signature chain_signature,'Blocking Wait Chain: '||decode(blocker_chain_id,null,

'',blocker_chain_id) blocker_chain

FROM v$wait_chains wc,

gv$session s,

gv$session bs,

gv$instance i,

gv$process p

WHERE wc.instance = i.instance_number (+)

AND (wc.instance = s.inst_id (+) and wc.sid = s.sid (+)

and wc.sess_serial# = s.serial# (+))

AND (s.final_blocking_instance = bs.inst_id (+) and s.final_blocking_session = bs.sid (+))

AND (bs.inst_id = p.inst_id (+) and bs.paddr = p.addr (+))

AND ( num_waiters > 0

OR ( blocker_osid IS NOT NULL

AND in_wait_secs > 10 ) )

ORDER BY chain_id,

num_waiters DESC)

WHERE ROWNUM < 101;

Current Process:2309 SID RAC1 INST #: 1

Blocking Process: from Instance Number of waiters:2

Wait Event:SQL*Net message from client P1: 1650815232 P2: 1 P3:0

Seconds in Wait:157 Seconds Since Last Wait:

Wait Chaing:1 : 'SQL*Net message from client '< ='enq: TM - contention'<='enq: TM - contention'

Blocking Wait Chain:

Current Process:2395 SID RAC1 INST #: 1

Blocking Process:2309 from Instance 1 Number of waiters:0

Final Block Process:2309 from Instance 1 Program: oracle@racdbe1.us.oracle.com (TNS V1-V3)

Wait Event:enq: TX - contention P1:1415053318 P2: 524316 P3:50784

Seconds in Wait:139 Seconds Since Last Wait:

Wait Chain:1 : 'SQL*Net message from client '< ='enq: TM - contention'<='enq: TM - contention'

Blocking Wait Chain:

B.對數據庫性能生成一個awr/statspack快照

C.收集最新的RDA

最新的RDA提供了大量額外關于數據庫配置和性能度量的信息可以用來檢測可能影響性能的熱點的后臺進程問題

有時數據庫不是真正的被hang住可是只是'spinning' cpu.可以使用以下方法來檢查服務器是hang還是spin如果一個操作執行的時間比期待的時間長或者這個操作損害了其它操作的性能時那么最好是檢查v$session_wait視圖.這個視圖顯示了在系統中會話當前正在等待的信息.可以使用下面的腳本來操作.

column sid format 990

column seq# format 99990

column wait_time heading 'WTime' format 99990

column event format a30

column p1 format 9999999990

column p2 format 9999999990

column p3 format 9990

select sid,event,seq#,p1,p2,p3,wait_time

from V$session_wait

order by sid

上面的查詢最少應該執行三次并比較其它查詢結果

列意思

sid-- 會話的系統標識符

seq#--序列號.當一個特定會話的等待一個新的事件時這個數字會增加.它能告訴你一個會話是否正在執行

evnet--會話正在等待的或最后等待的操作

p1,p2,p3--它們代表不同的等待值

wait_time--0指示這個會話正在等待的事件.非0指示這個會話最后等待的事件和會話正使用CPU

例如:

SID EVENT SEQ# P1 P2 P3 WTime

---- ------------------------------ ------ ----------- ----------- ----- ------

1 pmon timer 335 300 0 0 0

2 rdbms ipc message 779 300 0 0 0

6 smon timer 74 300 0 0 0

9 Null event 347 0 300 0 0

16 SQL*Net message from client 1064 1650815315 1 0 -1

如果腳本查詢的結果顯示正在等待一個enqueue等待事件那么你將需要檢查與你hang會話相關的鎖信息

column sid format 990

column type format a2

column id1 format 9999999990

column id2 format 9999999990

column Lmode format 990

column request format 990

select * from v$lock

Spinning

在spin的情況下事件通常來說是靜態的且會話不會是正在等待一個事件--而是在等待cpu(注意在極少數情況下,這個事件依賴于執行spin的代碼也可能不會靜態的.如果會自豪感是spin它將嚴重使用cpu和內存資源.

對于一個spin的情況重要的是要檢測會話正處于spinning的代碼.從事件的一些跡象說明通常需要對一個進程生成幾次的錯誤堆棧信息用來分析:

connect sys/sys as sysdba

oradebug setospid

oradebug unlimit

oradebug dump errorstack 3

這里的spid是操作系統標識符可以從v$process視圖是得到.

Hanging

在正常的情況下在v$session_wait視圖中的值應該是用每個會話執行的不同操作來替換.

在hang住的情況下對于一個或一組特定會話的所有系統事件將會是保持靜態狀態且進程不會消耗任何cpu和內存資源.鑒于會話現在沒有請求鎖定任何資源這就叫hang

在這種情況下可對實例轉儲系統狀態來獲得一些更詳細更有用的信息.

ALTER SESSION SET EVENTS 'IMMEDIATE TRACE NAME SYSTEMSTATE LEVEL XX';

在oralce9.2.0.6或oracle10.1.0.4或在oracle10g中最高的版本的中這里的xx是266.執行上面的命令在你的user_dump_dest目錄中會生成系統狀態跟蹤文件.

通過下面的查詢可以得到問題進程的進程ID

SELECT pid FROM v$process

WHERE addr =

(SELECT paddr FROM v$session

WHERE sid = sid_of_problem_session);

系統狀態轉儲文件包含了每一個進程的信息.可以通過搜索'PROCESS '來找到每一個進程的詳細信息.通過搜索'waiting for'來找到當前正在等待的事件.

總結

以上是生活随笔為你收集整理的oracle数据库延迟执行,如何诊断oracle数据库运行缓慢或hang住的问题的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。

上一篇：视频操作_02视频追踪：meanshif
下一篇：爬虫实战学习笔记_4 网络请求urlli