1.330 STANDBY_DB_PRESERVE_STATES

STANDBY_DB_PRESERVE_STATES controls whether user sessions, buffers, and other internal states of the instance are retained when a readable physical standby database is converted to a primary database. This parameter is meaningful on a physical standby database that is open in real-time query mode.
Property Description

Parameter type

String

Syntax

STANDBY_DB_PRESERVE_STATES = { NONE | SESSION | BUFFER | ALL }

Default value

NONE

Modifiable

No

Modifiable in a PDB

No

Basic

No

Oracle RAC

The same value must be used on all instances.

Values

  • NONE

    Nothing is retained. All sessions are disconnected and all buffers are flushed. This is the default value.

  • SESSION

    User sessions are retained. When the database is reopened as the primary, the retained sessions resume their operations as if nothing had happened. If the database (or an individual PDB) is not opened in the primary role, the sessions will be terminated.

  • BUFFER

    All current buffers are retained. Media recovery buffers are converted to current buffers and retained, if possible. When the database is reopened as the primary, the retained buffers are available for use, which may enable queries to run faster during the first few minutes of operation. If the database (or an individual PDB) is not opened in the primary role, the buffers will be flushed.

  • ALL

    This value is equivalent to setting both the SESSION and BUFFER values.

Note:

Sessions that have long running queries or are using database links will not be retained regardless of the setting of this parameter.

See Also: