A few weeks ago, Solr 6.0 was released, and right after we also released Solr 5.5.1. That means that most probably 5.5.x is the last in the 5.x series, so start preparing for an upgrade.
Why would you upgrade? Well, Changes gives you 40 bug-reasons and 33 feature-reasons 🙂 Let me highlight the coolest ones:
- SOLR-7560: Parallel SQL Support (DOC)
- SOLR-7986: JDBC Driver for SQL Interface (DOC)
- SOLR-7543: Basic graph traversal query
- SOLR-6273: Cross Data Center Replication (DOC)
Yes, you can now query Solr with SQL, although JOINs are not yet exposed to SQL (works at Streaming Expressions level). This may become huge with BI type applications.
And the ability to replicate your whole SolrCloud cluster to another data center with CDCR will also become important for many. Currently it is active-passive only (see illustration), but plans are to make it active-active in a future upgrade.
Besides, we now require Java 8, since Java 7 is no longer a supported product.
Also check out SOLR-3085 which I have contributed. Setting mm.autoRelax=true may help fix some issues with 0 hits due to stopwords and mm=100%.
Go and try it out 🙂