sql_trace/10046事件数据库诊断_alter system set events trace-优快云博客

sql_trace/10046事件是oracle提供的用于进行sql跟踪的手段，其内容包括sql的解析过程、sql的执行计划、绑定变量的使用、会话发生的等待事件，10046事件是oracle 的内部事件，是对sql_trace的加强。

规范的10046/sql_trace event 使用方法

alter session set tracefile_identifier='10046';
alter session set timed_statistics = true;
alter session set statistics_level=all;
alter session set max_dump_file_size = unlimited;
alter session set events '10046 trace name context forever,level 12';

alter session set events '10046 trace name context forever,level 12';---需要用户有alter session 权限

sql_trace的作用域：

1）对所有用户：

i）在参数文件中指定sql_trace=true

ii）alter system set sql_trace=true/false

2) 对当前用户：

启用当前session的跟踪：alter session set sql_trace=true;

结束跟踪：alter session set sql_trace=false;

3）对其他用户：

选择跟踪的进程（用户）

[sql] view plain copy print ?

sys@ORCL> select sid,serial#,username from v$session where username is not null;
SID SERIAL# USERNAME
---------- ---------- ------------------------------
142 14 HR
159 5 SYS

设置跟踪：

[sql] view plain copy print ?

sys@ORCL> exec dbms_system.set_sql_trace_in_session(142,14,true)
PL/SQL procedure successfully completed.

停止跟踪：

[sql] view plain copy print ?

sys@ORCL> exec dbms_system.set_sql_trace_in_session(142,14,false)
PL/SQL procedure successfully completed.

*************************************↖(^ω^)↗**********************************

10046事件是对sql_trace的增强，可分4个级别，具体如下：

1）level 1：等价于sql_trace

2）level 4：level 1+绑定值

3）level 8：level 1+等待事件跟踪

4）level 12：等价于level 1+level 4+level 8

10046事件的作用域：

1）对所有用户

i）在参数文件中修改：event=“10046 trace name context forever，level 12”

ii）alter system set events ‘10046 trace name context forever，level 8';

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

2）对当前用户

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

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

3）对其他用户

查询要跟踪的对象

[sql] view plain copy print ?

sys@ORCL> select sid,serial#,username from v$session where username is not null;
SID SERIAL# USERNAME
---------- ---------- ------------------------------
142 14 HR
159 5 SYS

执行跟踪

[sql] view plain copy print ?

sys@ORCL> exec dbms_system.set_ev(142,14,10046,8,'hr');
PL/SQL procedure successfully completed.

结束跟踪

[sql] view plain copy print ?

sys@ORCL> exec dbms_system.set_ev(142,14,10046,0,'hr');
PL/SQL procedure successfully completed.

*********************************~(@^_^@)~*************************************

由于trace文件的格式比较难以阅读，我们可以通过TKPROF工具进行格式化，最终生成符合我们阅读习惯的sql trace 文件。

格式如下：

tkprof tracefile outputfile [options]

其中，option选项的说明和使用，我们可以通过在bash环境罗列：

[sql] view plain copy print ?

[oracle@localhost ~]$ tkprof
Usage: tkprof tracefile outputfile [explain= ] [table= ]
[print= ] [insert= ] [sys= ] [sort= ]
table=schema.tablename Use 'schema.tablename' with 'explain=' option.
explain=user/password Connect to ORACLE and issue EXPLAIN PLAN.
print=integer List only the first 'integer' SQL statements.
aggregate=yes|no
insert=filename List SQL statements and data inside INSERT statements.
sys=no TKPROF does not list SQL statements run as user SYS.
record=filename Record non-recursive statements found in the trace file.
waits=yes|no Record summary for any wait events found in the trace file.
sort=option Set of zero or more of the following sort options:
prscnt number of times parse was called
prscpu cpu time parsing
prsela elapsed time parsing
prsdsk number of disk reads during parse
prsqry number of buffers for consistent read during parse
prscu number of buffers for current read during parse
prsmis number of misses in library cache during parse
execnt number of execute was called
execpu cpu time spent executing
exeela elapsed time executing
exedsk number of disk reads during execute
exeqry number of buffers for consistent read during execute
execu number of buffers for current read during execute
exerow number of rows processed during execute
exemis number of library cache misses during execute
fchcnt number of times fetch was called
fchcpu cpu time spent fetching
fchela elapsed time fetching
fchdsk number of disk reads during fetch
fchqry number of buffers for consistent read during fetch
fchcu number of buffers for current read during fetch
fchrow number of rows fetched
userid userid of user that parsed the cursor

我们通过一个例子来介绍对tkprof的使用：

[sql] view plain copy print ?

SQL> show parameter timed_statisticsNAME TYPE VALUE
------------------------------------ ----------- ------------------------------
timed_statistics boolean TRUE
SQL> show parameter max_dump_file_sizeNAME TYPE VALUE
------------------------------------ ----------- ------------------------------
max_dump_file_size string UNLIMITED

[sql] view plain copy print ?

sys@ORCL> alter session set sql_trace=true;
sys@ORCL> select * from hr.departments;
sys@ORCL> alter session set sql_trace=false; --最好是关闭跟踪，减小对性能的开销
sys@ORCL> exit; --在运行完查询后，要退出sql*plus（断开连接），这样才能完全关闭跟踪文件，使trace文件的所有信息都是有效的。

然后，我们就可以使用tkprof：

[sql] view plain copy print ?

[oracle@localhost ~]$ tkprof /u01/app/oracle/admin/orcl/udump/orcl_ora_5467.trc tkprof_think.txt
TKPROF: Release 10.2.0.1.0 - Production on Fri Jul 27 11:18:13 2012
[oracle@localhost ~]$ ls
tkprof_think.txt