Re: Query Performance and Optimization

[Christoph Kiehl]

Christoph Kiehl wrote:

I was digging a bit into Jackrabbit today and found another place where 
some caching did provide a substantial performance gain to queries which 
check one attribute for more than one value (like /foo/[EMAIL PROTECTED]:bar='john' 
or foo:bar='doe']). The BitSet in calculateDocFilter() is right now 
created twice for the query above. On large repositories this takes 
about 200ms per BitSet on my machine for a particular field. Caching 
these BitSets per IndexReader and field in a WeakHashMap with the 
IndexReader as a key gave me some real improvements. 

Replying to myself ;):

- I was referring to calculateDocFilter() in 
org.apache.jackrabbit.core.query.lucene.MatchAllScorer
- The achieved performance improvement varied between 30-60% depending on the 
actual query

Cheers,
Christoph