How to disable DNS Caching in Load Runner to avoid misleading performance results while testing Web services.
Protocol Type:
Web Service
Scenario/Flow:
Load Runner-->WIP(Global Load Balance)-->VIP(Local
Load Balancer)-->Host(Web Logic Server)
Note: WIP is a DNS service, the DNS reply can be cached
locally and some load tests could give misleading results like the response
time of web service request differs from the actual response time.
Issue:
Request was not reaching to WIP and it was not asking the
WIP for DNS resolution or DNS lookup(translation of the unique IP
address or domain of host in textual format to an IP address).
Symptom:
Local DNS Caching(Applications can cache the DNS reply, as
can local DNS servers).
Resolution:
As the Web Service protocol in Load Runner does not
have any option to disable DNS caching, we need to create a script using Web
HTTP/HTML protocol by converting all your SOAP or JMS calls using web_custom_request
in Web HTTP/HTML protocol. Once the migration is done, go to Runtime
Setting > Click on Preferences under Internet Protocol
group>Click Options button>Change the DNS Caching option to
NO under General Tab(by default it is set to YES).
