On a Neo4j causal cluster, it's possible to observe the following overflow error when executing very large transactions:

<TIMESTAMP> ERROR [c.n.c.p.i.ServerChannelInitializer] [raft-server] Exception in inbound for channel: [id: 0xeae558cd, L:/<IP>:<PORT> - R:/<IP>:<PORT>]
java.lang.IllegalArgumentException: Can't increase by <BYTES> as capacity(2147468002) would overflow 2147483647

This overflow problem is related to the RAFT protocol not being able to process transactions larger than 2 GB.
The error will also cause cluster instability, so it's important to prevent this problem.

To prevent this issue from happening, we need to explicitly define a transaction memory limit within the Neo4j configuration (neo4j.conf file), as follows:

Neo4j 4.x

dbms.memory.transaction.max_size=<VALUE>

Neo4j 5.x

db.memory.transaction.max=<VALUE>

Note:  Before Neo4j 5.15 and Neo4j 4.x and below, the maximum value that can be defined for this setting is 2Gb. A smaller value can be specified if required.

Detailed documentation regarding this specific setting is available in our documentation:

• Neo4j 4.x dbms.memory.transaction.max_size
• Neo4j 5.x db.memory.transaction.max