TurboIMAGE/XL Database Management System Reference Manual MPE/iX V6.5 (30391-90011)

Chapter 8 429
Using the Database Utilities
>>ENABLE
>>ENABLE
Enables the access, automatic deferred output, data prefetching, dumping, ILR, indexing,
MUSTRECOVER, logging, and recovery options.
Syntax
>>EN[ABLE] database name [ /maint word ] FOR option [, option ...]
For example:
ENABLE RETAIL FOR LOGGING
where RETAIL is the database name and LOGGING is an option .
Parameters
database name is the name of a TurboIMAGE/XL database being enabled.
maint word is the maintenance word defined by the database creator when the
database is created with DBUTIL. This word must be supplied by anyone
other than the database creator.
option is an option from the list provided and described below. More than one
option can be specified.
Options
ACCESS enables user access to the database.
AUTODEFER enables automatic deferred output for the database. With deferred output
the MPE/iX transaction manager is not used to log database modifications
to the transaction manager log file. Instead, AUTODEFER uses the
MPE/iX file system default mode. This mode keeps data pages in memory
for as long as possible until either lack of memory or the closing of a file
causes the pages to be written to disk. In this mode a system failure can
cause the loss of database integrity. ILR is not compatible with
AUTODEFER; therefore, deferred output should be used only in a batch
situation where the database has been backed up prior to batch
processing. ILR must be disabled prior to enabling AUTODEFER.
AUTODEFER can be used to increase I/O performance by disabling
Transaction Management (XM). However, ILR and roll-back recovery must
be disabled. You must consider performance and the ability to recover data
when determining whether to use AUTODEFER. Roll-forward logging can
be used to preserve consistency.
DSEM enables use of Dependency Semaphore for increased concurrency of