IBM Digital Experience 2015: Caching Techniques

The IBM Digital Experience Conference is full of beneficial technical information.  The IBM WebSphere Portal Performance Team Lead, Hunter Presnall presented on Caching Techniques.  These are some of the high points from the presentation.

With every version of WebSphere Portal performance is always an important item.  Caching is a very important part for helping any environment improve response times.

Where to cache?

Browser Cache

• Set the Cache-Control header for the response to set the max-age.
• This is the best performing cache due to the removal of network and application time.
• Static content is your best items to cache
  • Images
  • CSS
  • JavaScript
• Portal Support
  • Theme resources can have the Cache-Control header set by the Configured in the WP ConfigService Resource environment Provider can set the cache-control header that will be added to resources from theme elements and WebDAV.
  • Portal Page and Portlet Cache Control
    • NOTE: Portlets default to no cache so setting the cache control of the page will not be effective unless you also set the cache control of the portlets on the page too.  This is due to the system utilizing the least common denominator for the rendering cache control

Network Cache

• Only cache public items
  • Caching Proxies
  • HTTP server memory or disk cache
  • CDN (Content Delivery Network)
• IHS (IBM HTTP Server)
  • Always enable caching.  It is IBM recommended to use mod_disk_cache and not mod_mem_cache
    • mod_mem_cache is less supported and partially deprecated.  This can also significantly increase your memory needs as mem_cache is duplicated for different processes.
  • GZIP compression (mod_deflate)
    • Compress your HTML, CSS, and JavaScript. Do not compress Images or other binary data.
    • Depending on your load you may see a CPU utilization.
    • Ensure you only compress your responses at one level between the application server and the client browser.

Application Cache

• Dynacache
• Portal heavily utilizes DynaCache.
• Monitoring
  • Performance Monitoring Infrastructure (PMI)
  • Extended Cache Monitor
  • PortalCachePortlet
    • https://greenhouse.lotus.com/plugins/plugincatalog.nsf/assetDetails.xsp?action=editDocument&documentId=81637C45380C3B4E85257CEB00451825
• WCM Cache
  • Basic: non-personalized content
  • Advanced Caching
    • Site: same as Basic
    • Session: per user stored in session
    • User: per user stored in DynaCache
    • Secured: per group combination
    • Personalized: per PZN Profile
  • Pre-Rendering: utilized for static sites