HP 3000 Manuals HP 3000 Manuals
CHANGE BLOCKFACTOR
Changes the blocking factor of a data set.
Syntax
CHA[NGE] BLOCKF[ACTOR] DataSetName NewBlockFactor
Parameters
DataSetName is the name of the data set to be reblocked.
NewBlockFactor is the number of data set records in one block.
If zero is specified, it takes the value
calculated by DBSCHEMA.
Description
Use this command to change the blocking factor of a data set. When
selecting a blocking factor, remember that the resulting block length
must not be larger than the maximum block length for the data set. That
is, if the media record is 6 words and the maximum block length is 85,
the blocking factor cannot be greater than 14 (85/6=14). The default
maximum block size is 512, but it may have been redefined with a DBSCHEMA
$CONTROL command or with a previous CHANGE BLOCKMAX command.
The blocking factor must be a number that can be evenly divided into the
capacity.
NOTE If you change the blocking factor to a number that cannot be evenly
divided into the capacity, DBSCHEMA (called by the DBAPLUS program)
adjusts the capacity to a multiple of the new blocking factor
closest to the current capacity.
To change the maximum block size for a data set, use the CHANGE BLOCKMAX
command.
Example
>change blockfactor sales 16
In this example, the blocking factor of the SALES data set is changed to
16.
Before the change, the SALES data set entry in the schema looks like
this:
NAME: SALES ,D(11/14,18);
ENTRY: ACCOUNT ( CUSTOMER ( PURCH-DATE )),
STOCK# (!PRODUCT ),
QUANTITY ,
PRICE ,
TAX ,
TOTAL ,
PURCH-DATE ( DATE-MASTER ),
DELIV-DATE ( DATE-MASTER );
CAPACITY: 504(14); <---- blocking factor to be changed
After the change, the SALES data set entry in the schema looks like this:
NAME: SALES ,D(11/14,18);
ENTRY: ACCOUNT ( CUSTOMER ( PURCH-DATE )),
STOCK# (!PRODUCT ),
QUANTITY ,
PRICE ,
TAX ,
TOTAL ,
PURCH-DATE ( DATE-MASTER ),
DELIV-DATE ( DATE-MASTER );
CAPACITY: 504(16); <---- blocking factor changed