使用 Tkprof 分析 ORACLE 跟踪文件
Tkprof是一个用于分析Oracle跟踪文件并且产生一个更加清晰合理的输出结果的可执行工具。如果一个系统的执行效率比较低，一个比较好的方法是通过跟踪用户的会话并且使用Tkprof工具使用排序功能格式化输出，从而找出有问题的SQL语句。
一. TKPROF 命令语法：
TKPROF filename1, filename2 [ SORT = [ opion][,option] ]
[ PRINT = integer ]
[ AGGREGATE = [ YES | NO ] ]
[ INSERT = filename3 ]
[ SYS = [ YES | NO ] ]
[ [ TABLE = schema.table ] | [ EXPLAIN = user/password ] ]
[ RECORD = filename ]
相关说明：
filename1 指定的输入文件，可以是多个文件联起来。
Filename2 格式化输出文件。
SORT 在输出到输出文件前，先进程排序。如果省去，则按照实际使用的顺序输出到文件中。排序选项有以下多种：
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
相关文档：
什么是合并多行字符串（连接字符串）呢，例如：
SQL> desc test;
Name Type Nullable Default Comments
------- ------------ -------- ------- --------
COUNTRY VARCHAR2(20) Y &nb ......
1. 查询数据库现在的表空间
select tablespace_name, file_name, sum(bytes)/1024/1024 table_size from dba_data_files group by tablespace_name,file_name;
2. 建立表空间
CREATE TABLESPACE data01 DATAFILE '/oracle/oradata/db/DATA01.dbf' SIZE 500M;
3.删除表空间
DROP TABLESPACE data01 INCLUDING CONTENTS ......
（1）[Q]如何插入单引号到数据库表中
[A]可以用ASCII码处理，其它特殊字符如&也一样，如
insert into t values('i'||chr(39)||'m'); -- chr(39)代表字符'
或者用两个单引号表示一个
or insert into t values('I''m'); -- 两个''可以表示一个'
（2）[Q]随机抽取前N条记录的问题
[A]8i以上版� ......
// 执行跳过，跳过的结果在
execute dbms_logstdby.skip(stmt => 'DML',schema_name => '%', object_name => '%');
stmt的取值可以是：
http://download-west.oracle.com/docs/cd/B14117_01/appdev.101/b10802/d_lsbydb.htm#997290
// 跳过的内容记载在下面
select * from dba_logstdby_skip
......
Oracle log files : An introduction
The Oracle server maintains the redo Oracle log files to minimize the loss of data in the Database in case of an uncontrolled shutdown.
Online redo Oracle log files are filled with redo records. A redo record, also called a redo entry, is made up of a gr ......
