Neo4j

Good day, I've seen similar behavior once db doesn't have enough space for transaction log. Could you please verify if your system has enough disk space? Thanks, Alexander

Have you tried to grant access (chmod) to the neo4j user (or user that your are using) to /var/log/neo4j?

Could you please share a little bit more on topic? What code are you trying to execute? How does your repositories configured?

Merge actually creates a node if it doesn't exists; in the merge statement you also can specify data modification on required action, please check neo4j merge documentation - https://neo4j.com/docs/cypher-manual/current/clauses/merge/ Your last query...