熟悉oracle的同学，对tkprof应该不会陌生。今天用到tkprof，有些语法变得模糊起来。查看文档，重新梳理有关tkprof的有关知识，加深记忆。
通过tkfprof可以非常方便的跟踪诊断sql语句的执行效率。结合explain plan的使用，更是如虎添翼。
sql trace为我们查看某天sql 语句的性能信息提供了可能，通常sqltrace可以生成下面的统计信息：
Parse, execute, and fetch counts 解析 执行和抓取的动作数量CPU and elapsed times 花费在cpu和整个操作上的时间Physical reads and logical reads 物理读和逻辑读Number of rows processed 处理的记录数量Misses on the library cache 库缓存的丢失率Username under which each parse occurred 执行用户Each commit and rollback 每次的提交和回滚操作 （
tkprofl不会处理这些信息）Wait event data for each SQL statement, and a summary for each trace file 针对每条sql语句和所有的sql语句生成事件信息数据除此之外，如果在sql trace期间，跟踪的语句游标已经关闭，sql trace还会提供如下的行源信息 Row operations showing the actual execution plan of each SQL statementNumber of rows, number of consistent reads, number of physical reads, number of physical writes, and time elapsed for each operation on a row
语法格式：
[oracle@oadata trace]$ tkprof
Usage: tkprof tracefile outputfile [explain= ] [table= ]
[print= ] [insert= ] [sys= ] [sort= ]
table=schema.tablename Use 'schema.tablename' with 'explain=' option. --手动生成explain plan时，存储中间信息的临时表，默认为PROF$PLAN_TABLE
explain=user/password Connect to ORACLE and issue EXPLAIN PLAN. --手动生成explain时，连接数据库的用户名和密码
print=integer List only the first 'integer' SQL statements.--仅仅处理前integer数量的sql语句，如果我们需要生成脚本，该参数对脚本中包含的sql数量是不影响的
aggregate=yes|no
insert=filename List SQL statements and data inside INSERT statements.--生成脚本，该脚本会创建表，并把相关统计信息插入表，从而可以在数据库中查看
sys=no TKPROF does not list SQL statements run as user SYS. --是否包含sys用户生成的信息，如递归sql
record=filename Record non-recursive statements found in the trace file. --生成脚本，脚本包含跟踪文件中的非递归sql语句
waits=yes|no Record summary for any wait events found in the trace file.--记录等待事件信息
sort=option Set of zero or more of the following sort options: --对语句进行排序
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
sql trace与执行计划： 如果在sqltrace期间，sql语句的游标已经关闭，sqltrace中会包含执行计划的相关信息
SQL> show user
USER 为 "SCOTT"
SQL> explain plan for select object_id,object_name,object_type from tab1 where object_id = 1000;
已解释。
SQL> select * from table(dbms_xplan.display());
PLAN_TABLE_OUTPUT
----------------------------------------------------------------------------------------------------
Plan hash value: 2086140937
------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-