You can improve the HPL performance by preparing an environment
that is optimized for the particular load or unload job that you are
performing.
You must consider the following aspects of your load and
unload jobs:
Configuration-parameter values
Mode (express or deluxe)
Devices for the device array
Usage models
The onpload configuration parameters
The onpload configuration parameters
control the number of threads that onpload starts
and the number and size of the buffers that are used to transfer data.
The onstat options for onpload
The onstat utility has two options that
you can use to observe the behavior of database server threads during
express-mode loads.
Devices for the device array
On a data-load job, each device runs independently
of other devices. Thus mixing fast and slow devices does not adversely
affect the speed of the load.
Settings for a no-conversion load or unload job
A no-conversion load or unload is not highly CPU intensive
because no conversion is involved. In this case, the load or unload
is expected to be limited by the speed of the tape devices. No-conversion
loads and unloads are always completed in express mode.
An express-mode load with delimited ASCII
In an express-mode load with delimited ASCII, the load
or unload job is limited by the available CPU. The conversion to or
from IBM® Informix® types
to ASCII is the most expensive portion of these operations
HPL performance hints
In general, the performance of the High-Performance Loader (HPL) depends
on the underlying hardware resources: CPU, memory, disks, tapes, controllers,
and so on. Any of these resources could be a bottleneck, depending
on the speed of the resource, the load on the resource, and the particular
nature of the load or unload.
Release date: March 2013