Cognos Analytics

Although IBM Cognos Analytics doesn’t require a web server like Microsoft IIS or Apache HTTP Server to be configured for it, it is a best practice to do so as it is essential for  load balancing certain requests and serving static content like icons and image files efficiently.

Did you know that you can enable HTTP/2 on your web server today and that this may improve the responsiveness of some of your Cognos dashboards?

HTTP/2 is a networking protocol for low-latency transport of content. Compared to the traditional HTTP/1.1 which may very well be what your Cognos Analytics web server is operating in today, HTTP/2 offers two key advantages that may improve the load times of widgets in your dashboards.

1. Header compression
2. Increased concurrency of requests

The former is simply that the HTTP header size is much smaller in HTTP/2 compared to HTTP/1.1, and less is faster when it comes to transferring information.

The improved concurrency refers to the fact that HTTP/2 supports several requests on the same TCP connection.  Dashboarding in Cognos Analytics was engineered for the parallel processing of widgets, but HTTP/1.1 throttles the number of concurrent queries much more than HTTP/2. The following diagram illustrates how, for a dashboard with a high number of widgets, HTTP/2 allows for the complete set of widgets to load faster by enabling a greater number of them to be processed at the same time.

Another advantage of HTTP/2 is that the client/server connection is persistent. This means a TLS (the successor to SSL) handshake only happens once, rather than on each request.  For higher latency environments, the impact this can have on user wait times can be significant.

Here’s a few things to note before you get too exited about enabling HTTP/2:

• HTTP/2 is only supported over TLS, so if you’re not accessing your Cognos environment with an https:// at the beginning of the URL, it will fall back gracefully to using HTTP/1.1.
• Not all web browser versions support HTTP/2 and will connect using HTTP/1.1 instead. Most notable is Internet Explorer 11 from Windows 7.
• As a web browser is no longer limiting the number of concurrent queries, HTTP/2 will allow a busy dashboard to increase the workload on the Cognos server and on any underlying data servers in a way that was not possible with HTTP/1.1. Fewer users will now be able to apply much greater load to back-end servers.

To learn more about HTTP/2 including how to turn it on, please see the following sites

• Apache: https://httpd.apache.org/docs/2.4/howto/http2.html
• IIS: https://docs.microsoft.com/en-us/iis/get-started/whats-new-in-iis-10/http2-on-iis
• NGINX: https://www.nginx.com/blog/http2-module-nginx/#config