Gosha Emelyanov

Avoid deadlock on write transaction

1

I've noticed that writing relationship table [(here)](https://github.com/opencypher/morpheus/blob/9f500f5364c0ba14933d96d088d5a8501d4644ad/morpheus-spark-cypher/src/main/scala/org/opencypher/morpheus/api/io/neo4j/Neo4jPropertyGraphDataSource.scala#L202) containing dozens of millions of rows with large batches (default value in the configuration, 100000) generates a lot of warnings like this ```...

Deleting a graph from PropertyGraphDataSource

2

[The deleteGraph method](https://github.com/opencypher/morpheus/blob/9f500f5364c0ba14933d96d088d5a8501d4644ad/morpheus-spark-cypher/src/main/scala/org/opencypher/morpheus/api/io/neo4j/Neo4jPropertyGraphDataSource.scala#L142) doesn't take into account created constraints on the metaLabel. Problem is that `DETACH DELETE` doesn't remove associated constraints and indexes. That causes an error when a PropertyGraph...

Minor improvements

2

### What was fixed? This PR addresses the following issues: #4 #8 ### How? Now the model takes into consideration the current values of driving series. Also resolved the issue...