Elasticsearch 2.0 released

Released Elasticsearch 2.0. A major milestone and achievement of the whole team, and wonderful contributions from the community. New type of aggregations called pipeline aggs, simplified query DSL by merging query and filter concepts, better compression options, hardened security by enabling security manager, hardening of FS behavior (fsync, more checksums, atomic renames), performance, consistent mapping behavior, and many more. Also, it bundles Lucene 5 release, which includes numerous improvements.

tf–idf - best known weighting scheme in information retrieval

tf–idf, short for term frequency–inverse document frequency.
Best known weighting scheme in information retrieval
Good explanation: https://class.coursera.org/nlp/lecture/187

I have just released Allegro OpenSource: Elasticsearch reindex tool
http://allegrotech.io/elasticsearch-reindex-tool.html

Logstash roadmap

Logstash is a tool for managing events and logs. You can use it to collect logs, parse them, and store them for later use (like, for searching). Speaking of searching, logstash comes with a web interface for searching and drilling into all of your logs.

It is fully free and fully open source. The license is Apache 2.0, meaning you are pretty much free to use it however you want in whatever way.

Now we have also Logstash roadmap

Spring Cloud 1.0.0 Available Now

Spring Cloud provides tools for developers to quickly build some of the common patterns in distributed systems (e.g. configuration management, service discovery, circuit breakers, intelligent routing, micro-proxy, control bus, one-time tokens, global locks, leadership election, distributed sessions, cluster state). Coordination of distributed systems leads to boiler plate patterns, and using Spring Cloud developers can quickly stand up services and applications that implement those patterns. They will work well in any distributed environment, including the developer’s own laptop, bare metal data centres, and managed platforms such as Cloud Foundry.

More info here:
https://spring.io/blog/2015/03/04/spring-cloud-1-0-0-available-nowLokalizacja

Good article about lucene internals

You can read about lucene implementation concerning posting lists and filters here:

http://www.elasticsearch.org/blog/frame-of-reference-and-roaring-bitmaps/

Announcing MongoDB 3.0

Today MongoDB 3.0 is generally available; you can download now.