PREINIT (Pre-Format Index and Data Areas) › How to Use

How to Use

To pre-format an index area, execute DBUTLTY using the following command format:

►─ PREINIT AREA=IXX,IXXAREA=Iaa,DBID=n ┬─────────────────┬──────►
                                       └─ ,BLKSIZE=size ─┘
►─┬───────────────────────┬──┬──────────────┬──────────────────►◄
  └─ ,OLDEP= ─┬─ YES ◄ ─┬─┘  └─ ,VOLUMES=n ─┘
              └─ NO ────┘

Command

PREINIT

Invokes the function to pre-format index areas for CA Datacom/DB use.

Required Keywords

AREA=IXX

Identifies the area to be pre-formatted as an index.

Valid Entries:

IXX

Default Value:

(No default)

,IXXAREA=Iaa

Specify a specific index area to PREINIT using IXXAREA=Iaa where Iaa is an uppercase letter i (I) followed by two variable characters, aa, that can be XX or 00 through 99. Specify IXXAREA=IXX for the main index IXX. To specify the PREINIT of a separate index area to contain some of the key IDs within the database, use IXXAREA=Iaa as previously described.

As in the syntax diagram previously shown, when pre-initializing an index area, use AREA=IXX in combination with any valid value for IXXAREA= Iaa.

Valid Entries:

IXX or, Iaa, where aa can be 00 through 99 as previously described

Default Value:

(No default)

,DBID=n

Identifies the database.

Valid Entries:

DATACOM-ID of the database

Default Value:

(No default)

Optional Keywords

,BLKSIZE=size

The BLKSIZE= keyword allows you to select a block size other than the default.

BLKSIZE= can be used to specify an index block size of from 4096 bytes through 8192 bytes. The BLKSIZE= value remains in effect until the next initialization of the IXX. You must pick an optimal size for your device type, in a manner similar to how the data area block size is selected. See the description of BLKSIZE= in the required keywords in How to Use.

We do not recommend changing the block size from the default. For more information, see Controlling the Index Block Size.

Note: An OPEN error occurs if an attempt is made to open a database that has an index block size larger than the index buffer size. For more information about the ixxbfrsize parameter of the SYSPOOL MUF startup option, see the CA Datacom/DB Database and System Administration Guide.

Valid Entries:

4096 through 8192

Default Value:

4096 (or, for some device types, a little less)

,OLDEP=

Refers to old entry points. When OLDEP=NO is specified, the DBNTRY entry point, designated as the primary entry point since the early 1980s, is the only entry point supported. For compatibility with prior versions, OLDEP=YES is the default, allowing the use of older entry points such as CBLDBMS and DATACOM. Those older entry points, however, use index blocks limited to a maximum of 255 entries. If you specify OLDEP=NO, you ensure that DBNTRY is used. Using DBENTRY allows you to use index blocks that can hold a maximum of 8K entries. Therefore, if you want to use 8K index blocks, and for some performance enhancement, use OLDEP=NO.

Alternately, if a program attempts using an old entry point with an index initialized as OLDEP=NO, the request fails with a return code 39(090) CANNOT PROCESS OLD REQUEST.

Valid Entries:

YES or NO

Default Value:

YES

,VOLUMES=n

(z/OS only)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 a PREINIT 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, VOL=SER=(VOL001,VOL002,VOL003,VOL004,VOL005,VOL006), so that volumes 4/5/6 are 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.

Valid Entries:

the number n of volumes to be catalogued

Default Value:

(No Default)