Further considerations

This section presents considerations about composite databases that developers and administrators must be aware of.

Sharding an existing database

An existing database can be sharded with the help of the neo4j-admin database copy command. See Sharding data with the copy command for an example.

Composite database transactions

Composite databases do not support WRITE transactions that span across multiple graphs. To avoid common mistakes that may lead to data corruption, WRITE operations on more than one graph within the same transaction, are not allowed. Transactions with queries that read from multiple graphs, or read from multiple graphs and write to a single graph, are allowed.

Neo4j embedded

Composite databases are not available when Neo4j is used as an embedded database in Java applications. Composite databases can be used only in a typical client/server mode, when users connect to a Neo4j DBMS from their client application or tool, via Bolt or HTTP protocol.