Oracle 10046 trace文件分析
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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 |
参考：http://blog.itpub.net/29320885/viewspace-1223962/
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