5250 Connect User’s Guide
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Maximizing Performance of 5250 Logon Connection
To prevent 5250 Components from beginning execution on a connection that may
have been left on an invalid screen by a previous 5250 component, the Logon
Connection Resource allows the connection itself to check for the presence of the
launch screen. This is accomplished by using the option titled “Reuse connection
only if expression is true” on the Pool Info dialog of the Logon Connection. The
screen test you specify here is executed each time a 5250 Component completes
execution. If the test fails, exteNd Composer will immediately disconnect from
the host, possibly leaving a dangling UserID on the host. As noted before, the host
will eventually kill the user, but the UserID may be discarded from the pool if it is
accessed again before being killed, thereby reducing the pool size and
consequently overall performance.
Another reason to use the “Reuse connection only if true” option is that you can
perform very detailed tests against the screen to make sure it is your launch screen.
While Map Screen actions do perform a screen check, they only look at the
number of fields in the terminal data stream. In most cases, this is sufficient.
However, it is possible two different screens can have the same number of fields
in which case the expression based test that examines the content of the screen will
produce more rigorous results. A best practices approach mandates that you use
this feature all the time.
Static versus Dynamically Created Documents/Elements
In some Composer applications, users have a need to place various control,
auditing, and/or meta-data in an XML document. This document may or may not
be in addition to the actual elements/documents being processed (i.e. created from
an information source). If this document structure and data is dynamically created
by multiple Map actions (i.e. over 100) performance of the component and
therefore the entire service may suffer. To boost performance, create the portion of
the document structure without the dynamic content ahead of time, then load it
into the Service at runtime via an XML Interchange action and retain the Map
actions for dynamic content. This can boost performance as much as 30% in some
cases.
Creating a Logon Connection using a Session
Connection
Sometimes, you may want the extra level of control over session parameters that
a Logon Connection affords, without necessarily wanting to use pooling. In this
case, you can follow the procedure outlined below.
