Requests Are Not Succeeding

The following problems are addressed in this section:

• Is the Load Balancer Timeout Correct?

• Are the System Clocks Synchronized?

• Is the Application Server Communicating With HADB?

Is the Load Balancer Timeout Correct?

Description

When configuring the response-timeout-in-seconds property in the loadbalancer.xml file, you must take into account the maximum timeouts for all the applications that are running. If the response timeout it is set to a very low value, numerous in-flight requests will fail because the load balancer will not wait long enough for the Application Server to respond to the request.

Conversely, setting the response timeout to an inordinately large value will result in requests being queued to an instance that has stopped responding, resulting in numerous failed requests.

Solution

Set the response-timeout-in-seconds value to the maximum response time of all the applications.

Are the System Clocks Synchronized?

Description

When a session is stored in HADB, it includes some time information, including the last time the session was accessed and the last time it was modified. If the clocks are not synchronized, then when an instance fails and another instance takes over (on another machine), that instance may think the session was expired when it was not, or worse yet, that the session was last accessed in the future!

In a non-colocated configuration, it is important to synchronize the clocks on that machines that are hosting HADB nodes. For more information, see the Installation Guide chapter, “Preparing for HADB Setup.”

Solution

Verify that clocks are synchronized for all systems in the cluster.

Is the Application Server Communicating With HADB?

Description

HADB may be created and running, but if the persistence store has not yet been created, the Application Server will not be able to communicate with the HADB. This situation is accompanied by the following message:

WARNING (7715): ConnectionUtilgetConnectionsFromPool failed using
connection URL: connection URL

Solution

Create the session store in the HADB with a command like the following:

asadmin create-session-store --storeurl connection URL --storeuser haadmin 
--storepassword hapasswd --dbsystempassword super123