java.lang.StackOverflowError: null at org.neo4j.cypher.internal.compiler.v2_2.ast.rewriters.expandStar$$anonfun$1$$anonfun$apply$1.apply(expandStar.scala:35)

[ceefour]

neo4j 2.2.2

Error:

java.lang.StackOverflowError: null
    at org.neo4j.cypher.internal.compiler.v2_2.ast.rewriters.expandStar$$anonfun$1$$anonfun$apply$1.apply(expandStar.scala:35)
    at org.neo4j.cypher.internal.compiler.v2_2.replace.apply(Rewritable.scala:208)
    at org.neo4j.cypher.internal.compiler.v2_2.replace$$anon$2.expand(Rewritable.scala:198)
    at org.neo4j.cypher.internal.compiler.v2_2.ast.rewriters.expandStar$$anonfun$1$$anonfun$apply$1.apply(expandStar.scala:35)
...REPEATS...
    at org.neo4j.cypher.internal.compiler.v2_2.replace.apply(Rewritable.scala:208)
    at org.neo4j.cypher.internal.compiler.v2_2.replace$$anon$2.expand(Rewritable.scala:198)
    at org.neo4j.cypher.internal.compiler.v2_2.ast.rewriters.expandStar$$anonfun$1$$anonfun$apply$1.apply(expandStar.scala:35)

How to reproduce:

1. Clone https://github.com/ceefour/opencog-neo4j/tree/cypher-2.2.2-stackoverflow tag cypher-2.2.2-stackoverflow
2. Grab the file https://gist.github.com/ceefour/b546d8636766a3bc5056
3. Run ImportBio2App main class using arguments: Lifespan-observations_2015-02-21.scm ~/tmp/lifespan.neo4j

It will generate the error.

[jexp]

Does it generate a gigantic cypher statement (which is not recommended anyway) or many smaller ones?

[ceefour]

Yups, a gigantic Cypher

[jexp]

I think the parser was never meant to parse gigantic statements, and it will be very inefficient to plan and execute.

I very much recommend splitting it into many small similar, parametrized statements which can be executed in a batch (e.g. 1k simple statements http-request) but also concurrently (with 2.2.x concurrent write load is really high).

[ceefour]

It's not using HTTP though, but embedded.

What's the best practice when using smaller statements? 10000 statements in 1 transaction, or 10000 statements in 10000 transactions?

[jexp]

10k statements per tx are fine.
If you can write concurrently you can also do 1k statements per tx and then use 12 to 32 concurrent write threads.