The INIT Data Area option formats one (or all) data area(s) in a database. It updates the first block with control information. This first block is subsequently updated when maintenance is performed. The block size used is the size specified for the area in the Directory (CXX) definition.
Performing an INIT on a data area has no performance benefit. It should only be done before the first load, and then only if needed. An INIT of an Index or data area clears the utility history for that area (see Type H - Utility Function History Report).
The following topics are discussed on this page:
Use this function to allocate a new data area or data areas. A data area must be initialized before CA Datacom®/DB can use it. This is necessary only once for any data area unless you modify the block size to accommodate changes.
In Simplify mode, the function expects MUF to be enabled. This provides control and protection. If MUF is not enabled, this function should wait for MUF to enable. If you are required to execute the function without MUF enabled, for example if it is needed to allow restart to execute, the function must follow a function that can only run with MUF not enabled or it must follow a function to acknowledge MUF is not enabled, with SET OPTION1=MUF_NOT_ENABLED. It is possible (but we do not recommend) to use SET OPTION1=MUF_ENABLED_OR_DISABLED.
CA Datacom®/DB saves the data set name of the area in the Directory (CXX) at the time of the INIT. The data set name is then available for reporting. It is also available for dynamic allocation.
Depending on operating system requirements and operating system maximums, a data area can exist as one or more extents on one or more volumes, . If initializing an existing data set (DISP=SHR or DISP=OLD), CA Datacom®/DB formats all currently allocated tracks for use. If initializing a new data set (DISP=NEW), CA Datacom®/DB requests and formats the primary allocation only if one volume is provided. If multiple volumes are provided, CA Datacom®/DB requests secondary allocations until space has been allocated on the number of volumes specified. For a description of how the operating system handles secondary allocations, see your operating system JCL manual.
If the keyword VOLUMES= is specified with a number value that is less than the number of volumes provided, the INIT function only initializes the number specified in the VOLUMES= keyword. For example, for a DD statement with VOL=SER=(VOL001,VOL002,VOL003), without the VOLUMES= keyword DBUTLTY initializes 1 to 16 extents on VOL001, 1 to 16 extents on VOL002, and 1 (or more) extents on VOL003. But with the VOLUMES= keyword set as VOLUMES=2, DBUTLTY initializes 1 to 16 extents on VOL001 and one (or more) extents on VOL002. Unused extent possibilities on VOL002 and VOL003 are available for dynamic extend.
Environmental Requirements when MULTUSE=NO, Simplify NO, or MUF down
Environmental Requirements when MULTUSE=NO Simplify YES and MUF enabled
Environmental Controls when MULTUSE=NO, Simplify NO, or MUF down
Environmental Controls when MULTUSE=NO, Simplify YES, and MUF enabled
Environmental Requirements when MULTUSE=YES
Environmental Controls when MULTUSE=YES
You can execute this command in either Single User or with the MUF active. Execute the DBUTLTY function using the following command format:
►►─ INIT AREA=a,DBID=n ─┬───────────────────────┬─────────────────────────────►
└─ ,VERIFY= ─┬─ NO ◄ ─┬─┘
└─ YES ──┘
└─ ,MULTUSE= ─┬─ NO ◄ ─┬─┘ └─ OPTION1=REINIT ─┘
└─ YES ──┘
└─ ,VOLUMES=n ─┘
(For area level DBUTLTY control only.) In support of area level DBUTLTY control, specifying MULTUSE=YES in the INIT function for a data area allows a single area in a database to be initialized with no disabling of the other areas in the database. When MULTUSE=YES, the function executes in a format that is a combination of MUF and Single User modes. The database involved must be able to be opened for update in the MUF address space. The area, however, must have no tables open. Once begun, the function does not allow other tasks to open any tables in the area being processed. Other tables in the database, but not in the area, may be open for read or update in the same MUF. The actual data set open is performed in the utility region, and the JCL requirements are applied to the utility region.
The operating system performs the catalog portion of the DD statement DISP option when the DD statement is removed. This occurs at job step termination. Therefore, if you were to create a new data set with an INIT, do not expect the MUF to correctly open this area until after the step completes. This restricts the DBUTLTY functions that succeed when following a catalog change.
When you specify or allow the default of MULTUSE=NO in the INIT function for data areas, the function executes completely in Single User mode.
For more information about area level DBUTLTY control, see Area Level DBUTLTY Control.
You can specify both VERIFY=YES and DISP=NEW, but if you specify both the VERIFY=YES is ignored.
The n in VOLUMES=n is the maximum number of volumes to initialize. Without the VOLUMES= option, the number of volumes having specific VOLSER information is initialized. The VOLUMES= option allows more volumes to be catalogued as part of the data set and available to an EXTEND or dynamic EXTEND, while being effectively held in reserve without a specific allocation.
For example, you could specify VOLUMES=3 when using an INIT to initialize an area that needs 3 volumes, intending to only initialize the space on 3 volumes. But the JCL could specify 6 specific volumes, for example:
In this example, volumes 4/5/6 are therefore not allocated or used during the INIT but are available to a dynamic extend. In this case, the extra volumes would not need to be removed before another INIT.
The following shows the command to initialize the data Area DEM for database 1.
//jobname See the previous note and Required JCL.
// EXEC PGM=DBUTLTY,REGION=2M
//STEPLIB See the previous note and Required JCL.
//CXX DD DSN=cxx.data.set,DISP=SHR Directory data set
//aaannn (for bases 001-999) DD DSN=aaa.data.set,DISP=SHR Data area DEM data set bases 1-999
//aaannnn (for bases 1000-5000) DD DSN=aaa.data.set,DISP=SHR Data area DEM data set bases 1000-5000
//SYSIN DD * Command Input
Following is a sample report page. For an example report header, see Sample Report Headers.
This page of the report shows the following:
DEM - STATUS INFORMATION
DEVICE TYPE - 3380
BLOCK LENGTH - 1,024
BLOCKS/TRACK - 31
BLOCKS IN USE - 1
BLOCKS UNUSED - 154
TOTAL BLOCKS - 155
TOTAL TRACKS - 5
PERCENT FULL - 1
This page of the report shows messages indicating the status of the data area at successful completion of the initialization.