Today is Leonhard Euler’s birthday, and we’re celebrating by announcing a first Release Candidate for Neo4j 1.9, now available for download! This release includes a number of incremental changes from the last Milestone (1.9-M05). This release candidate includes the last set of features we’d love our community to try out, as we prepare Neo4j 1.9 for General Availability (GA).

Google is celebrating Euler’s birthday with this Doodle.
Neo4j rings it in with a 1.9 Release Candidate!


Key changes since the last milestone are as follows:


High Availability


  • Introduction of pseudo quorum writes. If half or more of the instances are unreachable (i.e. have gone down), the instance will stop accepting write requests and all subsequent transactions will time out. Transactions will be able to resume once quorum is re-established.


Backup


  • Neo4j now automatically determines what type of backup should be performed based on the contents of the target directory. -full and -incremental backup flags are now deprecated.


Cluster

  • The experimental mechanism for automatically assigning server ids based on the instance’s URI has been changed. The administrator must now explicitly set integer server ids in exactly the same manner as in 1.8.
  • We have removed an experimental feature introduced in earlier 1.9 milestones, which added the ability to specify a central cluster definition URI. This turned out to be underused and to introduce unneeded complexity.
  • It is now possible to introduce a new instance to the cluster to replace a failed one. This requires the new instance to have the same ID as the one that failed.
  • Cluster formation requires a majority of instances to be available, based on the instance count implied by initial_hosts
  • Fixes addressing cluster formation, when instances are concurrently started up
  • The cluster will explicitly deny instances from joining if they have a server_id that is already in use

Index Provider

  • Lucene upgraded to 3.6.2

Server

  • Introduces new welcome screen in the web UI, containing a guide to Neo4j, aimed at helping new users to find their way around the basics. Also several small aesthetic improvements

Cypher

  • Fixed #578 – problem with profiling queries that use LIMIT
  • Fixes #550 – problem when using START after WITH
  • Allows single node patterns in MATCH
  • Fixes problem for some patterns and all-nodes start points
  • Fixes #650 – issue when doing multiple aggregation expressions on the same identifier
  • Added timestamp function

Packaging

  • plugins/ subdirectory is searched recursively for server plugins

Manual
  • The HA Setup tutorial has been fully rewritten to update the latest functionality. It also provides two distinct paths in the examples: one for local testing, and one for production setup


As always with a release candidate, please download and examine this version thoroughly and help us spot anything that is amiss. We’re looking forward to the final 1.9 GA release in a short time.


Enjoy!


Philip Rathle & The Neo4j Team



















 

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