DB_LOST_WRITE_PROTECT

Property	Description
Parameter type	String
Syntax	DB_LOST_WRITE_PROTECT = { NONE | TYPICAL | FULL }
Default value	NONE
Modifiable	ALTER SYSTEM
Basic	No
Real Application Clusters	In RAC instances, the parameter value is system-wide.

DB_LOST_WRITE_PROTECT enables or disables lost write detection. A data block lost write occurs when an I/O subsystem acknowledges the completion of the block write, while in fact the write did not occur in the persistent storage.

When the parameter is set to TYPICAL on the primary database, the instance logs buffer cache reads for read-write tablespaces in the redo log, which is necessary for detection of lost writes.

When the parameter is set to FULL on the primary database, the instance logs reads for read-only tablespaces as well as read-write tablespaces.

When the parameter is set to TYPICAL or FULL on the standby database or on the primary database during media recovery, the instance performs lost write detection.

When the parameter is set to NONE on either the primary database or the standby database, no lost write detection functionality is enabled.

Note:

1. This parameter was introduced in 11g.

2. Query for the current value of the parameter

select name, value, isdefault, isses_modifiable, issys_modifiable,

isinstance_modifiable, isdeprecated, description

from v$parameter where upper(name) = ‘DB_LOST_WRITE_PROTECT’;

Oracle initializatoin parameters