All -
I apologize if this question has been asked before - I couldn't seem to
find a straightforward answer by researching it on google and stackoverflow.
I am trying to understand when I should use filter queries vs plain vanilla
queries. Here's what I understand:
* Filter queries can be much faster since as of SOLR 1.4 they are
parallelized with the main query and are cached in the filter cache. This is
in contrast with SOLR < 1.4 where the filter query was ran on the doc set
after the main query returned - essentially causing an O(n) operation.
* Filter queries do not affect document score. Use them if one doesn't want
the filter query to impact the score.
I've done some basic query performance testing on my SOLR instance,
which allows users to search via a faceted search interface. As such,
document relevancy is less important to me since I am performing exact match
searching. Comparing using filter queries with a plain query has yielded
remarkable performance. However, I'm suspicious of statements like 'always
use filter queries since they are so much faster'. In my experience, things
are never so straightforward. Can anybody provide any further guidance? What
are the pitfalls of relying heavily on filter queries? When would one want
to use plain vanilla SOLR queries as opposed to filter queries?
Thanks!
Josh
