Oracle 10046 trace文件分析

2016-03-20 16:29 abce 阅读(2058) 评论(0) 编辑收藏举报

生成10046 trace文件：

SQL> create table t10046 as select * from dba_objects;
 
Table created.
 
SQL> select file_id,block_id,blocks from dba_extents where segment_name='T10046';
 
   FILE_ID   BLOCK_ID     BLOCKS
---------- ---------- ----------
         1      94664          8
         1      94672          8
         1      94680          8
         1      94688          8
         1      94696          8
         1      94704          8
         1      94712          8
         1      94896          8
         1      94904          8
         1      94912          8
         1      94920          8
         1      94928          8
         1      94936          8
         1      94944          8
         1      94952          8
         1      94960          8
         1      95872        128
         1      96000        128
         1      96128        128
         1      96256        128
         1      96384        128
         1      96512        128
         1      96640        128
         1      96768        128
         1      96896        128
 
25 rows selected.
 
SQL> alter session set events '10046 trace name context forever,level 12';
 
Session altered.
 
#没有创建索引，会走全表扫描
SQL> select count(*) from t10046;
 
  COUNT(*)
----------
     86956
 
SQL> alter session set events '10046 trace name context off';

10046 trace 文件的内容：

=====================
PARSING IN CURSOR #140231913930616 len=27 dep=0 uid=0 oct=3 lid=0 tim=1458364346292404 hv=3335870169 ad='7bf41070' sqlid='awzvq6b3da
pqt'
select count(*) from t10046
END OF STMT
PARSE #140231913930616:c=10998,e=11061,p=217,cr=59,cu=0,mis=1,r=0,dep=0,og=1,plh=2130400753,tim=1458364346292403
EXEC #140231913930616:c=0,e=36,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,plh=2130400753,tim=1458364346292551
WAIT #140231913930616: nam='SQL*Net message to client' ela= 7 driver id=1650815232 #bytes=1 p3=0 obj#=-1 tim=1458364346292607
WAIT #140231913930616: nam='enq: KO - fast object checkpoint' ela= 3499 name|mode=1263468550 2=65555 0=1 obj#=-1 tim=145836434629669
1
WAIT #140231913930616: nam='direct path read' ela= 335 file number=1 first dba=94665 block cnt=55 obj#=88635 tim=1458364346297284
WAIT #140231913930616: nam='direct path read' ela= 1770 file number=1 first dba=94896 block cnt=72 obj#=88635 tim=1458364346299150
WAIT #140231913930616: nam='direct path read' ela= 912 file number=1 first dba=95872 block cnt=128 obj#=88635 tim=1458364346300730
WAIT #140231913930616: nam='direct path read' ela= 386 file number=1 first dba=96000 block cnt=128 obj#=88635 tim=1458364346301893
WAIT #140231913930616: nam='direct path read' ela= 299 file number=1 first dba=96128 block cnt=128 obj#=88635 tim=1458364346302928
WAIT #140231913930616: nam='direct path read' ela= 371 file number=1 first dba=96256 block cnt=128 obj#=88635 tim=1458364346304307
WAIT #140231913930616: nam='direct path read' ela= 236 file number=1 first dba=96384 block cnt=128 obj#=88635 tim=1458364346305513
WAIT #140231913930616: nam='direct path read' ela= 202 file number=1 first dba=96512 block cnt=128 obj#=88635 tim=1458364346306513
WAIT #140231913930616: nam='direct path read' ela= 381 file number=1 first dba=96640 block cnt=128 obj#=88635 tim=1458364346307527
WAIT #140231913930616: nam='direct path read' ela= 285 file number=1 first dba=96768 block cnt=128 obj#=88635 tim=1458364346309125
WAIT #140231913930616: nam='direct path read' ela= 324 file number=1 first dba=96896 block cnt=89 obj#=88635 tim=1458364346310304
FETCH #140231913930616:c=14998,e=19124,p=1240,cr=1243,cu=0,mis=0,r=1,dep=0,og=1,plh=2130400753,tim=1458364346311758
STAT #140231913930616 id=1 cnt=1 pid=0 pos=1 obj=0 op='SORT AGGREGATE (cr=1243 pr=1240 pw=0 time=19122 us)'
STAT #140231913930616 id=2 cnt=86956 pid=1 pos=1 obj=88635 op='TABLE ACCESS FULL T10046 (cr=1243 pr=1240 pw=0 time=24549 us cost=338
 size=0 card=70030)'
WAIT #140231913930616: nam='SQL*Net message from client' ela= 225 driver id=1650815232 #bytes=1 p3=0 obj#=88635 tim=1458364346312363
FETCH #140231913930616:c=0,e=1,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=0,plh=2130400753,tim=1458364346312405
WAIT #140231913930616: nam='SQL*Net message to client' ela= 2 driver id=1650815232 #bytes=1 p3=0 obj#=88635 tim=1458364346312426
 
*** 2016-03-19 13:12:37.876
WAIT #140231913930616: nam='SQL*Net message from client' ela= 11563756 driver id=1650815232 #bytes=1 p3=0 obj#=88635 tim=14583643578
76195
CLOSE #140231913930616:c=0,e=10,dep=0,type=0,tim=1458364357876316
=====================

10046 trace 文件内容分析：

1.数据库调用
含3个子分类：解析，执行和获取
这3个分类与通过调用DBMS_SQL的子例程DBMS_SQL.PARSE,DBMS_SQL.EXECUTE,DBMS_SQL.FETCH_ROWS来跑SQL的步调相一致
解析在跟踪文件中通常通过两个相邻的条目表示：第一个是PARSING IN CURSOR,第二个是PARSE。如下所示：

PARSING IN CURSOR #140231913930616 len=27 dep=0 uid=0 oct=3 lid=0 tim=1458364346292404 hv=3335870169 ad='7bf41070' sqlid='awzvq6b3da
pqt'
select count(*) from t10046
END OF STMT
PARSE #140231913930616:c=10998,e=11061,p=217,cr=59,cu=0,mis=1,r=0,dep=0,og=1,plh=2130400753,tim=1458364346292403

(1)PARSING IN CURSOR各项的具体含义

参数	说明
len	表示sql语句文本字节长度　　#"select count(*) from t10046"字节长度为27
dep	递归调用深度　　#本次调用深度为0
uid	解析用户标识符，对应于all_users.user_id以及v$sql.parsing_user_id　　#本次是以sys用户执行的，故uid=0
oct	oracle命令类型，对应于v$sql.command_type以及v$session.command　　#select对应类型是3
lid	解析模式标识符，对应于all_users.user_id以及v$sql.parsing_schema_id，可能与uid不同
tim	微秒单位时间戳，在关联的parse条目中通常比tim的值早一点
hv	哈希值，对应于v$sql.hash_value
ad	address，对应于v$sql.address
sqlid	sql id，对应与v$sql.sql_id

(2)PARSE各项的具体含义

参数	说明
c	cpu开销
e	运行时间
p	物理读
cr	一致读
cu	当前处理的数据块
mis	游标丢失，0表示软解析；1表示硬解析
r	被处理的数据行
dep	递归调用深度
og	优化目标。1:all_rows,2:first_rows,3:rule,4:choose。oracle 10g 后默认是all_rows
plh	执行计划的hash值。对应于v$sql_plan.plan_hash_value,v$sql_plan_statistics_all.plan_hash_value以及v$sqlstats.plan_hash_value
tim	时间戳，单位为微秒

2.执行计划，统计信息与STAT条目格式

一组STAT条目的每一行代表了形成语句结果的行源。所谓的行源，指从索引或表中检索的数据或者多表连接的中间结果(因为必须先进行两表连接)。
10g以后，STAT条目仅在TIMED_STATISTICS=TRUE,并且SQL_TRACE=TRUE时才被写入。请注意，若STATISTICS_LEVEL=BASIC(缺省为TYPICAL)时会隐式设置TIMED_STATISTICS=FASLE。

STAT #140231913930616 id=1 cnt=1 pid=0 pos=1 obj=0 op='SORT AGGREGATE (cr=1243 pr=1240 pw=0 time=19122 us)'
STAT #140231913930616 id=2 cnt=86956 pid=1 pos=1 obj=88635 op='TABLE ACCESS FULL T10046 (cr=1243 pr=1240 pw=0 time=24549 us cost=338
 size=0 card=70030)'

(1)stat说明

参数	说明
id	执行计划中指示行数据源顺序的标识符，通常一个执行计划的第一条stat行的id=1
cnt	被处理的行数
pid	父标识符，通常一个执行计划的第一条stat行的pid=0。通过比一个计划的父步骤高一个级别缩进的依赖步骤，tkprof和esqltrcprof使用id以及pid生成适当缩进的执行计划
pos	父步骤中的一个步骤的位置
obj	对象标识符，对应于all_objects.object_id和v$sql_plan.object#
op	执行的行数据源操作，比如表访问、索引扫描、排序、联合等，对应于v$sql_plan.operation。在10g中，在行数据源信息后面op的括号中包含实际语句执行指标
cr	一致性读
pr	物理读
pw	物理写
time	估计的运行时间，单位为微秒
cost	cbo计算的执行计划成本
size	估计的数量，单位为字节
card	估计的基数，即被处理的行数

3.等待事件和WAIT条目格式

WAIT #140231913930616: nam='SQL*Net message to client' ela= 7 driver id=1650815232 #bytes=1 p3=0 obj#=-1 tim=1458364346292607
WAIT #140231913930616: nam='enq: KO - fast object checkpoint' ela= 3499 name|mode=1263468550 2=65555 0=1 obj#=-1 tim=145836434629669
1
WAIT #140231913930616: nam='direct path read' ela= 335 file number=1 first dba=94665 block cnt=55 obj#=88635 tim=1458364346297284
WAIT #140231913930616: nam='direct path read' ela= 1770 file number=1 first dba=94896 block cnt=72 obj#=88635 tim=1458364346299150
WAIT #140231913930616: nam='direct path read' ela= 912 file number=1 first dba=95872 block cnt=128 obj#=88635 tim=1458364346300730
WAIT #140231913930616: nam='direct path read' ela= 386 file number=1 first dba=96000 block cnt=128 obj#=88635 tim=1458364346301893
WAIT #140231913930616: nam='direct path read' ela= 299 file number=1 first dba=96128 block cnt=128 obj#=88635 tim=1458364346302928
WAIT #140231913930616: nam='direct path read' ela= 371 file number=1 first dba=96256 block cnt=128 obj#=88635 tim=1458364346304307
WAIT #140231913930616: nam='direct path read' ela= 236 file number=1 first dba=96384 block cnt=128 obj#=88635 tim=1458364346305513
WAIT #140231913930616: nam='direct path read' ela= 202 file number=1 first dba=96512 block cnt=128 obj#=88635 tim=1458364346306513
WAIT #140231913930616: nam='direct path read' ela= 381 file number=1 first dba=96640 block cnt=128 obj#=88635 tim=1458364346307527
WAIT #140231913930616: nam='direct path read' ela= 285 file number=1 first dba=96768 block cnt=128 obj#=88635 tim=1458364346309125
WAIT #140231913930616: nam='direct path read' ela= 324 file number=1 first dba=96896 block cnt=89 obj#=88635 tim=1458364346310304

参数	说明
ela	运行时间，单位为微秒
p1	等待事件的第一个参数。对应于v$session_wait.p1
p2	等待事件的第二个参数。对应于v$session_wait.p2
p3	等待事件的第三个参数。对应于v$session_wait.p3
tim	时间戳
file#	绝对文件编号
block#	数据块号
blocks	数据块数量
obj#	对象编号，就是object_id
nam	等待事件的名称