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

76 Chapter3
Defining a Database
Set Part
creation.
increment is either the number of entries or the percentage of the initial capacity by
which the data set will be expanded each time its initialized space is
exhausted. If a percentage is used, the percent sign (%) must follow the
incremental amount. This increment parameter can only be used if the
initial capacity parameter is also specified. This number must be 1 to
32767 inclusive for percent, or 1 to 2
31
−1 (2,147,483,647) inclusive for
number of entries. If it is very low, there can be frequent expansions
leading to severe disk fragmentation. If it is very high, DBPUT may take a
long time to complete which could impact other database users.
The number of entries defined, or the entries calculated from the percent,
cannot exceed the maximum entry count minus the initial allocation. The
increment is adjusted to represent an even multiple of the blocking factor.
The increment is an optional parameter. If the increment is not specified
for the data set, or is zero, but the initial capacity is greater than zero,
then the increment for each expansion is defaulted to ten percent (10%) of
the initial capacity for the data set. If the initial capacity is equal to the
maximum capacity, or the initial capacity is zero, then this indicates the
data set cannot be expanded and increment is ignored.
Example
NAME: SALES,DETAIL(11/14,18),DISC1;
ENTRY: ACCOUNT(CUSTOMER(PURCH-DATE)),
STOCK#(!PRODUCT),
QUANTITY,
PRICE,
TAX,
TOTAL,
PURCH-DATE (DATE-MASTER),
DELIV-DATE (DATE-MASTER);
CAPACITY: 1008,504,112;
Description
The example above shows the detail data set SALES which will reside on Disc1. The
maximum capacity is 1008, the initial capacity is 504, and the increment is 112.
Another example is a detail data set defined as follows:
CAPACITY: 500000(10),10000,25%;
The maximum capacity is set at 500000 with a blocking factor of 10. It has an initial
capacity of 10000, but will be automatically expanded by 2500 when the initialized space is
exhausted. Since the incremental amount is defined as a percent, the percent is calculated
as a constant number based on the initial (or original) capacity (25% of 10000 is 2500.)
To allow dynamic expansion for a detail data set, specify the maximum capacity and the
initial capacity when defining the data set. If dynamic expansion is not needed for the data
set, the maximum capacity is the only required parameter.
Verify that there is enough disk space for a data set to be expanded. Performance may be
impacted by the number of entries incremented when a detail data set is dynamically