Thanks for your response Joe.
As per my understanding, I'm not referring to BIG-IP memory issue. I suspect it could be due to the iControl library which interacts with the device through Web Service. Following are the methods used to retrieve the statistical data.
interfaces.getGlobalLBWideIP().get_statistics(wideips);
interfaces.getGlobalLBPool().get_statistics(pools);
interfaces.getGlobalLBPoolMember().get_all_statistics(pools);
Below is the flow of logic I had implemented in the code.
1. Get the interfaces reference to the device
2. Using the interfaces reference, retrieve the statistical data for Objects (WideIP, Pool, PoolMember, etc.,) using the above specified methods
3. Store the retrieved data in my local database
I'll go through the source of iControl library to analyze the root cause.