Apache Solr is an open source and high performace search server based on Lucene, using XML/HTTP and JSON APIs.
It features hit highlighting, faceted search, caching, replication, and a Web administration interface. The project is currently under incubation at the Apache Software Foundation.
Product's homepage
What's New in This Release: [ read full changelog ]
· A read side REST API for the schema. Always wanted to introspect the schema over http? Now you can. Looks like the write side will be coming next.
· DocValues have been integrated into Solr. DocValues can be loaded up a lot faster than the field cache and can also use different compression algorithms as well as in RAM or on Disk representations. Faceting, sorting, and function queries all get to benefit. How about the OS handling faceting and sorting caches off heap? No more tuning 60 gigabyte heaps? How about a snappy new per segment DocValues faceting method? Improved numeric faceting? Sweet.
· Collection Aliasing. Got time based data? Want to re-index in a temporary collection and then swap it into production? Done. Stay tuned for Shard Aliasing.
· Collection API responses. The collections API was still very new in 4.0, and while it improved a fair bit in 4.1, responses were certainly needed, but missed the cut off. Initially, we made the decision to make the Collection API super fault tolerant, which made responses tougher to do. No one wants to hunt through logs files to see how things turned out. Done in 4.2.
· Interact with any collection on any node. Until 4.2, you could only interact with a node in your cluster if it hosted at least one replica of the collection you wanted to query/update. No longer - query any node, whether it has a piece of your intended collection or not and get a proxied response.
· Allow custom shard names so that new host addresses can take over for retired shards. Working on Amazon without elastic ips? This is for you.
· Lucene 4.2 optimizations such as compressed term vectors.