IMS restricted updates

You must have the following prerequisites to enable the restricted update feature:

• IMS 15.1 or IMS 15.2 with PH26604
• z/OS 2.4
• RREPL parameter in the database section of the DFSDFxxx member must be set to ABEND, STATUS, or NONE
• Facility class DFS.DB.RREPL.* defined with update access permit for selective users

You can use a new attribute RREPL (Read-or-Replication only) for the database to determine whether a user can make updates. You can use the type-2 commands UPDATE DB and UPDATE AREA with the RREPL parameter to enable or disable the Restricted Update mode on full-function databases, including partitions, and Fast Path areas:

UPDATE DB NAME(DB List) SET(RREPL(ABEND | STATUS | NONE))
UPDATE AREA NAME(Area List) SET(RREPL(ABEND | STATUS | NONE))

RREPL

Specifies whether the database (or area) is in Read-or-Replication-only mode where reads are allowed for any program, but updates are allowed only for replication programs and authorized users, and the action to take when this mode is enabled.

STATUS

If an update is attempted by a nonreplication and unauthorized program, the status code RR is returned on any DL/I call that would have resulted in an update.

ABEND

If an update is attempted by a nonreplication and unauthorized program, the program is terminated with the user abend U3303.

NONE

The database (or area) is not in a Read-or-Replication-only mode.

The following guidelines and restrictions apply to the RREPL parameter:

• The RREPL parameter cannot be combined with any other UPDATE DB or UPDATE AREA command options.
• The RREPL parameter cannot be set on a catalog database. The command will fail and indicate that it is an IMS defined resource and the action cannot be completed. RC=0 is issued when the UPDATE DB command is used with wildcard (*), but the catalog is not impacted.
• The RREPL parameter cannot be set on an MSDB. The command will fail and indicate that the RREPL parameter is not valid for an MSDB.
• GSAM databases are not supported. If the UPDATE DB command is used to enable Restricted Update mode on a GSAM database, RC=0 is issued, and no action will be taken.
• If the RREPL parameter set on a Fast Path or HALDB database, its value is propagated to Fast Path areas or to HALDB partitions.
• The RREPL parameter that is specified on a database is retained across WARM, ERE, and ERE COLDCOMM restarts.
• During COLD, ERE COLDBASE, and ERE COLDSYS restarts, the RREPL parameter will be set on all databases, areas, and partitions based on the value that is specified in the database section of the DFSDFxxx member.
• Updates are allowed from Fast Path utilities (Create, Compare, Scan, Delete, and Reorg) and full-function utilities (OLR and OIC) regardless of the RREPL value on the database.

A default RREPL value for all the databases and areas can be set by using the RREPL keyword in the database section of the DFSDFxxx member during a cold restart:

RREPL = ABEND | STATUS | NONE | NA

You can find the RREPL value associated with a database or area by using the type-2 QUERY DB and QUERY AREA commands, for example:

QUERY DB NAME(DB List) STATUS(RREPL)
QUERY DB NAME(DB List) SHOW(STATUS)

QUERY AREA NAME(Area List) STATUS(RREPL)
QUERY AREA NAME(Area List) SHOW(STATUS)

RREPL

Sets the STATUS() filter to return information about databases that have the Restricted Update RREPL value set to ABEND or STATUS.

The following sample RACF command defines the facility class and grants USRT002 and USRT005 permission to update the database:

RDEF FACILITY DFS.DB.RREPL.* UACC(NONE)
PERMIT DFS.DB.RREPL.* CLASS(FACILITY) ID(USRT002, USRT005) ACCESS(UPDATE)

The following log record changes were made for this feature:

• Log record 22: The RREPLAF byte is added to indicate Restricted Update mode on an area.
• Checkpoint record 4006: RREPL flags are added to the CHKDDFG2 byte to indicate Restricted Update mode on an area.
• Checkpoint record 4084: The area level RREPL flag byte DMACRRAF is stored in 4084.