The filter caching features in Solr allow for precise control over how filter queries are handled in order to maximize performance. Solr has the ability to specify if a filter is cached, specify the order filters are evaluated, and specify … Continued
I’ve often seen mistaken descriptions of Solr as just “a http wrapper around Lucene”. Unfortunately that mischaracterization was never nipped in the bud early enough and has continued to be repeated in many places such as press articles (where it … Continued
Solr has had full featured Field Collapsing and Grouping since 2010. The CollapsingQParserPlugin, which was recently committed, provides an alternative approach with more specific design goals. Design Goals The initial CollapsingQParserPlugin requirements were driven by a Solr ECommerce user. The … Continued
Solr took another step toward increasing it’s NoSQL datastore capabilities, with the addition of realtime get. Background As readers probably know, Lucene/Solr search works off of point-in-time snapshots of the index. After changes have been made to the index, a … Continued
Lucene’s default ranking function uses factors such as tf, idf, and norm to help calculate relevancy scores. Solr has now exposed these factors as function queries. docfreq(field,term) returns the number of documents that contain the term in the field. termfreq(field,term) … Continued
I previously introduced Solr’s Result Grouping, also called Field Collapsing, that limits the number of documents shown for each “group”, normally defined as the unique values in a field or function query. Since then, there have been a number of … Continued
Solr 1.4 contains a new feature that allows range queries or range filters over arbitrary functions. It’s implemented as a standard Solr QParser plugin, and thus easily available for use any place that accepts the standard Solr Query Syntax by … Continued
One of the many performance improvements in the upcoming Solr 1.4 release involves improved filtering performance. Solr 1.4 filters are both faster (anywhere from 30% to 80% faster to calculate intersections, depending on configuration), take less memory (40% smaller), and … Continued
With CPU cores constantly increasing, there has been some major work done in Lucene/Solr to increase the scalability under multi-threaded load. Read-only IndexReaders One bottleneck was synchronization around the checking of deleted docs in a Lucene IndexReader. Since another thread … Continued
Having performance issues with Solr’s faceted search and certain types of fields? Help has arrived in the form of a new Solr faceting algorithm! This new faceting implementation dramatically improves the performance of faceted search, making it suitable for a … Continued
