User guide

Improving Performance
Using ENFORM Efficiently
058058 Tandem Computers Incorporated 5–11
By default, the approximate extent sizes are determined as follows:
For the primary extent size of the target file, ENFORM uses whichever is larger:
the size (in bytes) of the largest input file divided by 2048
the largest primary extent size of all the input files.
For the secondary extent size of the target file, ENFORM uses whichever is larger:
the largest secondary extent size of all the input files
the size determined for the primary extent of the target file
The default extent sizes used by ENFORM are satisfactory in many cases. In other
cases, however, especially if the target file or one of the input files is very large, the
default extent sizes are either too small or too large.
Fortunately, you can control the extent sizes. One way to control the extent sizes is to
estimate the number of target records and set the @TARGET-RECORDS Option
Variable clause to that number. ENFORM, then, uses the number specified to
determine the primary and secondary extent sizes for the target file. When
@TARGET-RECORDS is specified, ENFORM uses the following formula to determine
the size of both the primary and secondary extents:
(number of target records * target-record-length)/20480
The most accurate way to control the primary and secondary extent sizes of the target
file is to set both the @PRIMARY-EXTENT-SIZE and @SECONDARY-EXTENT-SIZE
Option Variable clauses appropriately.
Changing the Nondisc
Environment
Desirable changes to the nondisc environment reduce the number of processes
competing for a CPU, the number of processes competing for a system, and the
number of processes competing for a network. Possible changes are:
Placing the compiler/report writer process and a server query processor in
different CPUs.
Sharing query processors.
Reducing network traffic.
Process Placement
To reduce the number of processes competing for a CPU, start a server query
processor in a different CPU than the one that contains the disc process for the files to
be accessed. If possible start the compiler/report writer process in a different CPU
than the one containing either the server query processor or the disc process.
Starting a server query processor in a different CPU than the one containing the
compiler/report writer is useful in reducing problems with shortpool (an area of
shared memory) on Tandem NonStop Systems.
Remember to use the ?ATTACH command to identify the server query processor.