Maintaining state on the server – PB Docs 126

Maintaining state on the server

Using a stateless component

The Web DataWindow can run in a fully stateless server environment. Variables
in the Web page keep information about the rows being viewed and any
changes the user makes; this information is communicated to the
server component as needed so that the component can restore its
state each time it is called. Restoring its state includes retrieving
data from the database each time the page is reloaded, including
each time the user navigates to another page.

Operating in a stateless mode minimizes use of server resources
but can decrease performance. The client maintains the state of
the server component in string form and the information is sent
back and forth with every request. Also, when state is not maintained
on the server, the component must connect to the database and retrieve
data each time it is called. If the component server does not do
connection caching, response time for the client could be very slow.

Using a stateful component

You can increase performance by maintaining state on the server.
To maintain state, the page server’s session object keeps
a reference to the server component. If the server component is
running in EAServer, you must
mark the component as a stateful object and set a timeout value
for the component. Failing to set a timeout value if you are using
the component as a stateful object will result in orphaned instances
of the component on the server.

Maintaining state on the server provides faster response time
if the same component is accessed again. However, it also increases
the server resources used for each client connection.

To minimize impact on server resources, a short timeout on
a session lets the server get rid of a component that might not
be requested again. If the component is called again, its state
can be restored from the client state information. When the number
of hits on a page is expected to be large, setting a shorter timeout
reduces the number of instances that need to be maintained simultaneously.

Marking the object as stateful

To mark the component as a stateful object, set the component’s com.sybase.datawindow.serverSideState
property in EAServer Manager or call
the SetServerSideState method in a server-side script:

You should not set the
property for the HTMLGenerator126 component in EAServer Manager.

Setting timeout values

To set the timeout value for the HTMLGenerator126 component,
open its Component Properties dialog box in EAServer Manager
and set the property. Timeout
values are specified in seconds; a value of 0 means the component
never times out.

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