学会使用官方文档

·       学会使用官方文档，在网站tahiti.oracle.com上查找V$session的描述信息，查出dbms_stats包的信息，并截图贴出来。

http://tahiti.oracle.com/     这是Oracle所有文档的统一入口，在这里可以找到数据库  应用服务  合并应用等所有的参考文档

我们数据库版本：Release 11.2.0.1.0

1.Oracle Database, 11g Release 2 (11.2)      所以我们应该查这个文档

2.左上角找到 Master Boot List官方文档的索引

3.如果想查看《初始化视图+数据字典+动态性能视图》请参考《Reference》

4.选择Part III Dynamic Performance Views 这个部分中search：v$session，结果中排在第一行的就是v$session信息，列举了每个字段的含义，v$session相应的命令

V$SESSION displays session information for each current session.

Column

Datatype

Description

SADDR

RAW(4 | 8)

Session address

SID

NUMBER

Session identifier

SERIAL#

NUMBER

Session serial number. Used to uniquely identify a session's objects. Guarantees that session-level commands are applied to the correct session objects if the session ends and another session begins with the same session ID.

AUDSID

NUMBER

Auditing session ID

PADDR

RAW(4 | 8)

Address of the process that owns the session

USER#

NUMBER

Oracle user identifier

USERNAME

VARCHAR2(30)

Oracle username

COMMAND

NUMBER

Command in progress (last statement parsed); for a list of values, seeTable 9-2. These values also appear in the AUDIT_ACTIONS table.

OWNERID

NUMBER

Identifier of the user who owns the migratable session; the column contents are invalid if the value is 2147483644

For operations using Parallel Slaves, interpret this value as a 4-byte value. The low-order 2 bytes represent the session number and the high-order bytes represent the instance ID of the query coordinator.

TADDR

VARCHAR2(8)

Address of the transaction state object

LOCKWAIT

VARCHAR2(8)

Address of the lock the session is waiting for; NULL if none

STATUS

VARCHAR2(8)

Status of the session:

• ACTIVE - Session currently executing SQL
• INACTIVE - Session which is inactive and either has no configured limits or has not yet exceeded the configured limits
• KILLED - Session marked to be killed
• CACHED - Session temporarily cached for use by Oracle*XA
• SNIPED - An inactive session that has exceeded some configured limits (for example, resource limits specified for the resource manager consumer group or idle_time specified in the user's profile). Such sessions will not be allowed to become active again.
  

dbms_stats包信息在《PL/SQL Packages and Types Reference》文档中找，也是利用书列表，在这个文档中查询如下关键字即可找到
 141  DBMS_STATS

Using DBMS_STATSThis section contains topics which relate to using the DBMS_STATS package.

·         Overview                               概述

·         Types                                    包类型

·         Constants                              常数

·         Operational Notes                   操作说明

·         Deprecated Subprograms       不用的子过程

·         Examples                                例子，这段是非常常用的部分

这是DBMS_STATS包在官方文档中的描述

EXEC DBMS_STATS.GATHER_TABLE_STATS ('hr', 'employees');   这是我们经常使用的分析表统计信息的存储过程。