Kbase 19085: OPEN CLIENT: Performance Tuning Tip for Output Temp-Tables
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
01/09/1999 |
|
OPEN CLIENT: Performance Tuning Tip for Output Temp-Tables
Title: OPEN CLIENT: Performance Tuning Tip for Output Temp-Tables
KnowledgeBase Number: 19085
Creation Date: 01-SEP-99
Modified Date:
This document applies to: Progress 9.0A and higher
Version and Release Number: 9.0B
Summary:
When writing a piece of 4GL code which will be accessed via the Open
Client Toolkit and which returns an temp-table it is always a good
idea to also define an output parameter which returns back the number
of records in the temp-table.
This information can be put to good use on the client side by allowing
you to "size" the object you are going to be using to store the data
which you retrieve from the temp-table.
For instance, it is common in Java to store this information in a
vector. By default a new vector will allocate enough space to hold
ten (10) objects. Each new object added to the vector beyond the
first ten will cause a new vector to be created that has a size of
"old vector size + 1". Once the new vector is allocated Java must
copy all of the objects from the old vector to the new one.
Depending on how many records are involved this can become quite a
time and resource consuming task.
By returning the number of records in the temp-table you can
preallocate the vector with an initial size that exactly matches your
needs (thereby saving considerable time and resources).
The same rule applies in Visual Basic when storing the data in a
variant array. The ReDim statement can be used to resize the array
to the proper size required to hold the data and avoid time and
resource consuming reallocations.