Observations with Blueriq 10.5

Relevant Blueriq properties

blueriq.web-resources: the location (URL) of additional or overridden webresources

blueriq.web-resources.cache-key-seed:

blueriq.web-resources.cache-period-seconds:the cache period for all static webresources. When null, default behavior is to rely only on 'Last-Modified' header. When 0, caching is disabled. When > 0, the number of seconds to cache a resource client-side (browser).

HTTP 1.1 versus HTTP 2.0

HTTP 1.1. can only perform one request per connection, resulting in latency, HTTP 2.0 fixes this by introducing mulitplexing, which allows for multiple requests and responses to be handled by a single TCP connection at the same time.

In HTTP/1.1 it was quicker to download a single file as opposed to several smaller files. As a result it was best practice to concatenate your site’s CSS and JS. In a HTTP/2 era, HTTP requests are cheap, therefore creating a single concatenated file is often unnecessary and an anti-practice for two reasons:

1. The concatenated file would often contain components not required by the current page. For example, your blog page might load components that are only used on your checkout pages.
2. If a single component changed then the entire concatenated file would need to be invalidated from the browser cache.

Both of the above increase the amount of data which needs to be downloaded from the server to the browser. However, concatenation still does have its place due to compression ratios. Generally, larger files yield better compression results, thus reducing the total overall file size of your page.

HTTP 2.0 support

Tomcat 8.5 upgrade to HTTP 2.0: http://tomcat.apache.org/tomcat-8.5-doc/config/http.html#HTTP/1.1_and_HTTP/1.0_Support

Tomcat 8.5 Connector configuration: http://tomcat.apache.org/tomcat-8.5-doc/config/http.html

JBoss EAP 7.0: https://access.redhat.com/documentation/en-US/Red_Hat_JBoss_Enterprise_Application_Platform/7.0/pdf/Configuration_Guide/Red_Hat_JBoss_Enterprise_Application_Platform-7.0-Configuration_Guide-en-US.pdf

Websphere: it seems that Websphere currenlty does not support HTTP 2.0 (https://github.com/http2/http2-spec/wiki/Implementations)

Gzip compression

Enabling HTTP/2 alone can have a significant impact on your site’s performance, but additional best practices such as gzipping assets ensure optimal load times.Static files such as CSS and JS should be compressed by the server before sending them to the browser. This can reduce file sizes by up to 90%, which can significantly reduce the time it takes to download each asset.

Concatenation

In HTTP 2.0, concatenation isn't required anymore to improve performance. We can now send (potentially) hundreds of requests in one connection, so we don't have to bundle files together anymore. Concatenation was a way to cheat the 6-connections-open-at-one-time limit. That limit doesn't exist in HTTP/2. In fact, concatenation could be counter productive--what if you're loading a bunch of CSS that doesn't get used on a some of your pages? You're just loading extra bytes and that can slow down rendering of your page. In HTTP/1, it was often worth avoiding an extra round trip, but in HTTP/2 it probably isn't.

Further reading: https://deliciousbrains.com/performance-best-practices-http2/