Varnish Cache Invalidation

by Roman Heinrich

Solutions from Varnish:

  • Default approach
  • Hashtwo/Hashninja
    Hashtwo maintains an additional hash, in addition to the main hash that links objects and content in Varnish. You can put whatever you want into the hash and it will maintain a many-to-many relationship between keys and objects
    So, in the example above the content presentation layer could spit out the same list of articles in a header and hashtwo will maintain pointers from article numbers to cached object. The hash is pretty efficient and won't require much overhead.
  • Super Fast Purger, video

How Fastly deals with it:

Bans vs Purges:

Home-Grown Solutions:

Database Triggers:

Some Varnish Links:

Caching Logged in Users