I have submitted a patch to allow Solr's RequestHandlers to suppress the creation of HTTP caching headers. It makes no sense for example to cache responses for the admin pages and the update handlers. There is another patch that allows partial responses with timeout. This responses should not be cached as well.

Requests that end up in an exception should not be cached as well.

The patch is registered as SOLR-505 in Apache's JIRA.

As SOLR-127: Make Solr more friendly to external HTTP caches is now committed to the Solr codebase here some thoughts about how to set good values for the "Cache-Control" HTTP header for Solr. See http://wiki.apache.org/solr/SolrConfigXml#HTTPCaching about how to set the values.

When I talk about shared caches this also means browser caches.

Rules of thumb:

Apache Solr is an efficient and easy to use search server based on the well known search library Apache Lucene.

It is very flexible and has many features (like the really cool facetting function). It uses a simple RESTful HTTP interface to query and to change data in your index.

I submitted some patches to the Solr codebase:

• NGramFilterFactory and EdgeNGramFilterFactory