Data Build Manual
Customizing SQL-LOAD Output
Customizing Data Build
6–26 099331 Tandem Computers Incorporated
D
specifies descending order.
E
control fields to be modified in an E61 user exit before the data is sorted.
DFSORT then collates the data in ascending order using the format (f)
specified.
Composite keys are acceptable; the AC format can be specified on a field basis.
Note that computational data is the same on IBM and Tandem and should be ordered
in standard IBM collating sequence.
SQL LOAD Performance
Improvement
Data Build is very efficient in loading SQL data. It builds maximum data blocks, up to
32000 characters long, which minimizes the number of data transfers to SQLUTIL.
The SQLUTIL process can consume 100% of a CPU. Much of SQLUTIL processing is
to validate each column of data. A 300 character row takes longer if there are 30
columns of 10 characters each than if there are 10 columns of 30 characters each.
Data Build performance can be enhanced by running the conversion program in a
different CPU than the SQL processes. This provides much better performance than
can be achieved using a standard SQLCI LOAD operation without Data Build because
of the following:
Input data processing is overlapped with SQLUTIL processing.
Input data conversion from EBCDIC to ASCII is removed from SQLUTIL; the data
conversion and blocking can occur simultaneously with SQLUTIL.
In a standard Data Build environment:
The conversion program is named $ZBLD.
Only one SQL-LOAD process can run at one time (only one $ZBLD can be active).
The SQLMSGS program is named $ZBLDE and the SQLCI message output is to
$ZBLDE.
The conversion program and the SQL processes all run in the same CPU.
To run the conversion program in a separate CPU from the SQL processes, create a
new OBEY (command) file and run it outside of Data Build. This can be done anytime
after the BUILD DDL (F2) step is completed.
1. Exit Data Build.
2. FUP DUP ZZLOAD,NEWLOAD
ZZLOAD contains the SQLCI LOAD command(s). Use this because it contains the
correct record and block size that will be sent from the conversion program.