- Configuration Type
- Database manager
- Applies to
-
- Database Server with local and remote clients
- Database Server with local clients
- Partitioned Database Server with local and remote clients
- Satellite Database Server with local clients
- Parameter Type
- Configurable
- Default [Range]
- -1 [ 1e-10 - 1 ] A value of -1 will cause the parameter
value to be reset based on the running of the measurement program.
The CPU speed, in milliseconds per instruction, is used by the SQL
optimizer to estimate the cost of performing certain operations. The
value of this parameter is set automatically when you install the database
manager based on one of the following:
- Data from the db2spec.dat file located in the
cfg sub-directory. For example, in AIX-based environments
this file is located in the $DB2INSTANCE/sqllib/cfg
directory. This file contains SPECint92** benchmark results.
Information from this file will be used if SPECint92 benchmark data can be
located for both of the following:
- The machine on which the database manager instance is running
- The IBM RISC System/6000 model 530H. (SPECint92 data is used to
calibrate machines relative to the 530H which is why the data for the 530H is
required.)
| Note: | You may update the db2spec.dat file if you have SYSADM
authority. You should carefully follow the instructions contained in
that file.
|
- Output from a program designed to measure CPU speed. This program
is executed, if benchmark results are not available for any of the following
reasons:
- The platform does not have support for the db2spec.dat
file
- The db2spec.dat file is not found
- The data for the IBM RISC System/6000 model 530H is not found in the file
- The data for your machine is not found in the file.
You can explicitly set this value to model a production environment on your
test system or to assess the impact of upgrading hardware. By setting
it to -1, cpuspeed will be re-computed.
Recommendation: You should only adjust this parameter if
you want to model a different environment.
The CPU speed is used by the optimizer in determining access paths.
You should consider rebinding applications (using the REBIND PACKAGE command)
after changing this parameter.