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V$PARAMETER

原创 Oracle 作者:sunwgneuqsoft 时间:2007-12-01 09:20:45 0 删除 编辑

V$PARAMETER

V$PARAMETER displays information about the initialization parameters that are currently in effect for the session. A new session inherits parameter values from the instance-wide values displayed by the V$SYSTEM_PARAMETER view

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Column

Datatype

Description

NUM

NUMBER

Parameter number

NAME

VARCHAR2(64)

Name of the parameter

TYPE

NUMBER

Parameter type:

  • 1 - Boolean
  • 2 - String
  • 3 - Integer
  • 4 - Parameter file
  • 5 - Reserved
  • 6 - Big integer

VALUE

VARCHAR2(512)

Parameter value for the session (if modified within the session); otherwise, the instance-wide parameter value

ISDEFAULT

VARCHAR2(9)

Indicates whether the parameter is set to the default value (TRUE) or the parameter value was specified in the parameter file (FALSE)

ISSES_MODIFIABLE

VARCHAR2(5)

Indicates whether the parameter can be changed with ALTER SESSION (TRUE) or not (FALSE)

ISSYS_MODIFIABLE

VARCHAR2(9)

Indicates whether the parameter can be changed with ALTER SYSTEM and when the change takes effect:

  • IMMEDIATE - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect immediately.
  • DEFERRED - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect in subsequent sessions.
  • FALSE - Parameter cannot be changed with ALTER SYSTEM unless a server parameter file was used to start the instance. The change takes effect in subsequent instances.

ISMODIFIED

VARCHAR2(10)

Indicates whether the parameter has been modified after instance startup:

  • MODIFIED - Parameter has been modified with ALTER SESSION
  • SYSTEM_MOD - Parameter has been modified with ALTER SYSTEM (which causes all the currently logged in sessions' values to be modified)
  • FALSE - Parameter has not been modified after instance startup

ISADJUSTED

VARCHAR2(5)

Indicates whether Oracle adjusted the input value to a more suitable value (for example, the parameter value should be prime, but the user input a non-prime number, so Oracle adjusted the value to the next prime number)

DESCRIPTION

VARCHAR2(64)

Description of the parameter

UPDATE_COMMENT

VARCHAR2(255)

Comments associated with the most recent update

V$PARAMETER2

V$PARAMETER2 displays information about the initialization parameters that are currently in effect for the session, with each list parameter value appearing as a row in the view. A new session inherits parameter values from the instance-wide values displayed in the V$SYSTEM_PARAMETER2 view.

Presenting the list parameter values in this format enables you to quickly determine the values for a list parameter. For example, if a parameter value is a, b, then the V$PARAMETER view does not tell you if the parameter has two values (both a and b) or one value (a, b). V$PARAMETER2 makes the distinction between the list parameter values clear.

Column

Datatype

Description

NUM

NUMBER

Parameter number

NAME

VARCHAR2(64)

Name of the parameter

TYPE

NUMBER

Parameter type:

  • 1 - Boolean
  • 2 - String
  • 3 - Integer
  • 4 - Parameter file
  • 5 - Reserved
  • 6 - Big integer

VALUE

VARCHAR2(512)

Parameter value for the session (if modified within the session); otherwise, the instance-wide parameter value

ISDEFAULT

VARCHAR2(6)

Indicates whether the parameter is set to the default value (TRUE) or the parameter value was specified in the parameter file (FALSE)

ISSES_MODIFIABLE

VARCHAR2(5)

Indicates whether the parameter can be changed with ALTER SESSION (TRUE) or not (FALSE)

ISSYS_MODIFIABLE

VARCHAR2(9)

Indicates whether the parameter can be changed with ALTER SYSTEM and when the change takes effect:

  • IMMEDIATE - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect immediately.
  • DEFERRED - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect in subsequent sessions.
  • FALSE - Parameter cannot be changed with ALTER SYSTEM unless a server parameter file was used to start the instance. The change takes effect in subsequent instances.

ISMODIFIED

VARCHAR2(10)

Indicates whether the parameter has been modified after instance startup:

  • MODIFIED - Parameter has been modified with ALTER SESSION
  • SYSTEM_MOD - Parameter has been modified with ALTER SYSTEM (which causes all the currently logged in sessions' values to be modified)
  • FALSE - Parameter has not been modified after instance startup

ISADJUSTED

VARCHAR2(5)

Indicates whether Oracle adjusted the input value to a more suitable value (for example, the parameter value should be prime, but the user input a non-prime number, so Oracle adjusted the value to the next prime number)

DESCRIPTION

VARCHAR2(64)

Description of the parameter

ORDINAL

NUMBER

Position (ordinal number) of the parameter value. Useful only for parameters whose values are lists of strings.

UPDATE_COMMENT

VARCHAR2(255)

Comments associated with the most recent update

说明:

1, V$PARAMETER是当前session的初始化参数情况,而V$SYSTEM_PARAMETER则是当前实例范围内的默认的初始化参数。如果当前session内修改了相关的参数,那么V$PARAMETERV$SYSTEM_PARAMETER中的相应参数值就会不同。V$PARAMETER中的ISMODIFIED字段就会变成MODIFIEDalter session)或者是SYSTEM_MODalter system

2, V$PARAMETER2中的记录基本和V$PARAMETER相同,他们的区别主要在于对含有逗号的多个值的字符的参数的表达方式。举个例子,如果初始化参数中说明数据库有三个控制文件,那么在V$PARAMETER仅会存在一条关于control_files的记录,而在V$PARAMETER2中则会存在三条关于control_files的记录,每条记录标志都表示一个仅仅表示一条控制文件的地址,这三条记录通过ORDINAL来区分

3,V$SYSTEM_PARAMETERV$SYSTEM_PARAMETER2之间的关系与V$PARAMETER2V$PARAMETER相同

V$SPPARAMETER

V$SPPARAMETER displays information about the contents of the server parameter file. If a server parameter file was not used to start the instance, then each row of the view will contain FALSE in the ISSPECIFIED column.

Column

Datatype

Description

SID

VARCHAR2(80)

SID for which the parameter is defined

NAME

VARCHAR2(80)

Name of the parameter

VALUE

VARCHAR2(255)

Parameter value (null if a server parameter file was not used to start the instance)

ISSPECIFIED

VARCHAR2(6)

Indicates whether the parameter was specified in the server parameter file (TRUE) or not (FALSE)

ORDINAL

NUMBER

Position (ordinal number) of the parameter value (0 if a server parameter file was not used to start the instance). Useful only for parameters whose values are lists of strings.

UPDATE_COMMENT

VARCHAR2(255)

Comments associated with the most recent update (null if a server parameter file was not used to start the instance)

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