Neo4j 4.0 Milestone Release 3

Release Date: 8 November 2019

We are proud to announce the second public early release of our Neo4j Database – Neo4j Enterprise Edition 4.0 Milestone Release 3 (in short Neo4j EE 4.0 MR3). This release is distributed publicly: we encourage you to try out all the new features. Neo4j 4.0 will be available within Neo4j Desktop Canary Version. Neo4j 4.0 is the core technology of the Neo4j Graph Platform.

Important Information

This milestone release is a beta version and it should not be used in production. Issues in the release may lead to data corruption and eventually data loss. This version is considered “feature complete”, although we may consider to add, modify or remove features at the last minute: users and developers are therefore advised to plan the use of the new features with caution.

Highlights

Multiple databases available at runtime
Java and Javascript Reactive drivers with Server-to-Client flow control
New index population algorithm for the native index provider
A new, experimental version of Spring Data Neo4j based on reactive drivers (SDN/RX)
New features in schema-based security and Role Based Access Control
New features in sharding and federated data with Neo4j Fabric.

The Release Notes and changelog for the previous Milestone Release, Neo4j 4.0 EE MR2, are available here.

Detailed Changes and Docs

For a list of fixes and improvements, please see the changelog below. A preview of the documentation is available here.

Available Packages

Available Linux Repositories

Upgrading to Neo4j EE 4.0 MR3

In order to migrate from Neo4j 3.5 to Neo4j EE 4.0 MR3, follow the migration guide available here.

Neo4j 4.0 MR3 Changelog

Kernel

Signature change for procedures: db.awaitIndex and db.resampleIndex take index name instead of pattern. Procedures db.createIndex, db.createUniquePropertyConstraint and db.createNodeKey take list of labels and properties instead of combined pattern, ‘:Label(property)’ -> [‘Label’], [‘property’].
The settings for the automatic page cache warmer are now supported.
Upgrade commons-compress to 1.19
Fulltext procedure can not create index with duplicate entity tokens
Switch transaction state to be allocated off heap by default.
Refactoring of db.indexes() procedure
Expose heap usage metrics as part of neo4j provided metrics
Expose nodes and relationships counters as part of neo4j provided metrics
Remove connectors as group settings
Move and rename bolt/https ssl_policy settings
Rework to make Config.Builder accept typed Objects instead of Strings
The consistency checker no longer logs DEBUG messages about the full text indexes failing to register transaction state providers or procedures. These were harmless to begin with, so now they are gone.
Starting a database that needs recovery will no longer wait for a uniqueness index to be rebuilt if the uniqueness index has no uniqueness constraint associated with it
Improve error message for returning relationships that are deleted in the same transaction.
Fix bug that broke settings that used relative paths when using neo4j-admin backup.
Monotonic time tracking for transaction termination monitor
Added possibility to log long running queries
Consistency check now verify structural consistency of indexes
Added possibility to prefetch files into page cache
Added metrics for total store size (per database)
Fixed a bug where Distinct combined with MapProjection could cause some results to be removed because they were incorrectly seen as not distinct.
Upgrade commons-compress due to security fix.

Cypher

Add ability to disable role management
Decrease the chance of getting Found no solution for block with size 0 by reducing the number of solutions considered
When calling procedures with parameters of the wrong type, the error message has been improved to make this clear.
Create index and create constraint are no longer idempotent
Fix a planning problem where the planner wasn’t using the index after nodes have been deleted.
Combining index read, DISTINCT, and MERGE could in some situations end up with an error saying Uh oh… There was no slot for…
Solved a bug in compiled runtime where complex NodeHashJoins sometimes led to wrong result.
WGS-84 points will now properly validate their input coordinates. Values for latitude should always lie in the interval [-90, 90], any other value outside this range will throw an exception. Values for longitude should always lie in the interval [-180, 180], any other value outside this range will now be wrapped around to fit in this range.
Support database access/start/stop privilege
Removal of the REST API UserService endpoint
Support index, constraint and token management privileges
Fixes bug in slotted runtime, when a property is read from index and then a node property of the same name is updated later in the query. E.g.:
```
MATCH (n:Label)
WHERE n.prop > 0
 WITH collect(n.prop) AS ns
MATCH (n:Label) SET n.prop = 0
```
Enhance split function to take multiple delimiters
Adding ProcedureCallContext to Context that can be used by procedures. This will give procedures information about the context in which they were called, specifically which return items were requested via yield. Based on this, the procedure can safely decide to skip calculating values that are not yielded anyway. The procedures db.labels and db.relationshipTypes have taken advantage of this for performance optimizations.
Solved a bug in slotted runtime where complex NodeHashJoins sometimes led to wrong result.
Bound calculated selectivity of range seek to exact match selectivity…
Allow queries like:

OPTIONAL MATCH (a) MATCH (a)-->(b)

without a WITH between the clauses.

Adding ProcedureCallContext to Context that can be used by procedures. This will give procedures information about the context in which they were called, specifically which return items were requested via yield. Based on this, the procedure can safely decide to skip calculating values that are not yielded anyway. The procedures db.labels and db.relationshipTypes have taken advantage of this for performance optimizations.
Cypher now supports executing sub-queries. This enables, among other things, processing results of a union query, which was not possible before. The syntax for this looks like:
```
CALL { MATCH (x:X) RETURN x 
       UNION
       MATCH(x:Y) RETURN x
     } RETURN x ORDER BY x.foo 
```
Upgrade Apache Shiro to 1.4.1 to mitigate DoS vulnerability
Post-planning property read pushdown
Queries with variables defined before optional matches that contain OR predicates and can be planned as UNION queries were failing to retain the incoming variables.
Allows queries like:

MATCH (n) WHERE id(n)=20.0 RETURN n

to return the node with the id 20.

Procedures can now get information from ProcedureCallContext about the name of the database it is running on and if it is in the system database.

Causal Clustering

No longer try to connect to members which are long gone.
Use pooled buffers in store copy
Make chunk size configurable in store copy and increase default from 8K to 32K
Load external config file for akka.

Browser

Drag and drop cypher and grass files anywhere to import
Detect operating enviromentments more generically
Upgrade neo4j-driver to 1.7.5
Handle Infinity and -Infinity results correctly
Now displaying clickable urls in table and graph views
Export :history
Give user more connection feedback + add connection timeout configuration
Export query result records as JSON
Support additional :param definition. See :help params in neo4j-browser for instructions.
Use GraphQL version of Relate-API when available (in Neo4j Desktop)
UI fixes on :server user add and :server user list commands
Fix regression in write-code guide name
Revert “Use GraphQL version of Relate-API when available (in Neo4j Desktop)”.

Cypher Shell

Added modes: verbose/plain. Verbose displays more information and is intended for interactive use. Plain displays only the data from queries, intended for scripting
Added multiline statement support
Added option (–encryption) to choose between encrypted and unencrypted communication with the server
Added option –debug to get additional information in case of errors
Made semicolons optional for shell commands
Added version of connected Neo4j to welcome message
Fixed lack of interactive detection on Windows. Now always uses interactive mode on Windows by default
If non-interactive mode is desired (for scripting) then a new flag –non-interactive has been added
Insist that username is not empty
Fallback to plain bolt:// when url scheme is bolt+routing://
Fixed incorrect handling of bangs [!] in usernames/passwords
empty password gives a more descriptive error message
Fixed handling of pipes on Windows
cypher-shell now available in standalone Debian and RPM packages
Added tabular output format
automatically select output format when terminal is interactive or not
Fix periodic commit statements
Fixed startup crash on Alpine Linux
upgrading to latest version of driver
Assigning cypher expressions to parameters
update params display to show new params setting
adding support for spatial and temporal datatype
upgrading to driver 1.6.1
Don’t send parameter lambdas to server
Upgrade to java 11
Stream results of autocommit queries
Turn encryption off by default
Allows providing Cypher parameters as command line arguments with –param “name => value”.
Support for passing a cypher file via -f or –file to cypher-shell
Support interactively executing Cypher statements from a file via :source statements.cypher.

Packaging

Fixed parsing of neo4j.conf on Windows to allow users to specify additional jvm arguments such as jdk.serialFilter.

Misc

Remove self signed certificate.
Additional netty exception logging
Added info level logging of raft (pre)voting decisions
Fix leak in akka distributed metadata
Optionally use jdk.serialFilter to avoid java serialization exploits
Startup script has been fixed to run on java11 in all bash variants.

Recent Database Releases

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Release Notes: Neo4j 4.0 Milestone Release 3