best way to increase performance

If the Rest call returns a different data set - ie - a call to a weather service - you should make the call using Java Restful API ( javax.servlet.http.HttpSession) and display the results.  This will not impact performance.

Also - here is some performance tips -- Performance tuning tips | 6.x

I see that you prefer session over cookie to store frequently used response.

Thanks for the quick response smacdonald2008

Yeah - its better to develop an AEM service to invoke a 3rd party Restful service - see  --

Scott's Digital Community: Creating Adobe Experience Manager services that invoke third party Restful web services

Overall I would say, see what you can cache. For example in the browser / dispatcher, after this look at optimizing the code.

Thanks Mac. you are very helpful

feike_visser no Session-failover in AEM means, AEM user session will be lost if any publish server in the publish network is lost? if this is the case with AEM then storing response in session is not a good idea right? please help me make a better choice between cookie or javax.servlet.http.HttpSession(from request as attribute) for my application.

smacdonald2008 feike_visser Can you help me with my last query?

"restful services from AEM frequently"

Use Java code like:

DefaultHttpClient httpClient = new DefaultHttpClient();

  HttpGet getRequest = new HttpGet("http://maps.googleapis.com/maps/api/distancematrix/json?origins=Vancouver%20BC&destinations=San%20Francisco&sensor=false");

  getRequest.addHeader("accept", "application/json");

  HttpResponse response = httpClient.execute(getRequest);