Problem in return graph query

Hi, I’m trying to return graph in a simple query as below:

val myGraph = graph.cypher(
    s"""MATCH (n:Disease {name:"acne"})<-[r]-(m:Disease) 
    |CONSTRUCT
    |MERGE ALL n, m, r 
    |RETURN GRAPH""".stripMargin).graph

but I’m facing this error:

org.opencypher.v9_0.util.SyntaxException: Invalid input 'n': expected whitespace, comment, '=', node labels, MapLiteral, a parameter, a relationship pattern, ON, FROM GRAPH, CONSTRUCT, LOAD CSV, START, MATCH, UNWIND, MERGE, CREATE UNIQUE, CREATE, SET, DELETE, REMOVE, FOREACH, WITH, CALL, RETURN, UNION, ';' or end of input (line 3, column 11 (offset: 69))
	at org.opencypher.v9_0.parser.Base$$anonfun$parseOrThrow$1.apply(Base.scala:139)
	at org.opencypher.v9_0.parser.Base$$anonfun$parseOrThrow$1.apply(Base.scala:127)
	at scala.collection.immutable.List.map(List.scala:273)
	at org.opencypher.v9_0.parser.Base$class.parseOrThrow(Base.scala:127)
	at org.opencypher.v9_0.parser.CypherParser.parseOrThrow(CypherParser.scala:22)
	at org.opencypher.v9_0.parser.CypherParser.parse(CypherParser.scala:29)
	at org.opencypher.v9_0.frontend.phases.Parsing$.process(Parsing.scala:26)
	at org.opencypher.v9_0.frontend.phases.Parsing$.process(Parsing.scala:22)
	at org.opencypher.v9_0.frontend.phases.Phase$$anonfun$transform$1.apply(Phase.scala:35)
	at org.opencypher.v9_0.frontend.helpers.package$$anonfun$closing$1.apply(package.scala:23)
	at org.opencypher.v9_0.frontend.helpers.package$$anonfun$closing$1.apply(package.scala:23)
	at org.opencypher.v9_0.frontend.helpers.package$.using(package.scala:31)
	at org.opencypher.v9_0.frontend.helpers.package$.closing(package.scala:23)
	at org.opencypher.v9_0.frontend.phases.Phase$class.transform(Phase.scala:34)
	at org.opencypher.v9_0.frontend.phases.Parsing$.transform(Parsing.scala:22)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.v9_0.frontend.phases.PipeLine.transform(Transformer.scala:59)
	at org.opencypher.okapi.ir.impl.parse.CypherParser$class.process(CypherParser.scala:59)
	at org.opencypher.okapi.ir.impl.parse.CypherParser$.process(CypherParser.scala:39)
	at org.opencypher.okapi.relational.api.graph.RelationalCypherSession$$anonfun$3.apply(RelationalCypherSession.scala:138)
	at org.opencypher.okapi.relational.api.graph.RelationalCypherSession$$anonfun$3.apply(RelationalCypherSession.scala:138)
	at org.opencypher.okapi.relational.api.graph.RelationalCypherSession.time(RelationalCypherSession.scala:106)
	at org.opencypher.okapi.relational.api.graph.RelationalCypherSession.cypherOnGraph(RelationalCypherSession.scala:138)
	at org.opencypher.okapi.relational.api.graph.RelationalCypherSession.cypherOnGraph(RelationalCypherSession.scala:63)
	at org.opencypher.okapi.api.graph.PropertyGraph$class.cypher(PropertyGraph.scala:104)
	at org.opencypher.okapi.relational.impl.graph.ScanGraph.cypher(ScanGraph.scala:43)
	at Main$.delayedEndpoint$Main$1(Main.scala:58)
	at Main$delayedInit$body.apply(Main.scala:20)
	at scala.Function0$class.apply$mcV$sp(Function0.scala:34)
	at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
	at scala.App$$anonfun$main$1.apply(App.scala:76)
	at scala.App$$anonfun$main$1.apply(App.scala:76)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:35)
	at scala.App$class.main(App.scala:76)
	at Main$.main(Main.scala:20)
	at Main.main(Main.scala)

I couldn’t find a documentation to check correctness of my query. What part of my query is wrong? Thanks

CAPS version: 0.2.0 Spark Version: 2.2 Scala Version: 2.11.8

[DarthMax]

Yes so one problem you seem to be encountering here is that the Sparks planning time is quite long at times - this happens irregardless of the data size. You can use PrintRelationalPlan.set() before running any query to print the relational plans that are compiled from the Cypher query.

Yes, you can simply try to run graph.cache, this will cache all the dataframes that make up the graph.

We are working on a real documentation which will be published soon 😃

Best, Max

[DarthMax]

Hej Hamed,

you seem to be using a slightly wrong syntax. CAPS currently does not use the MERGE keyword to express graph construction.

To achieve what you want you could run the following query

val myGraph = graph.cypher(
    s"""MATCH (n:Disease {name:"acne"})<-[r]-(m:Disease) 
    |CONSTRUCT
    |  CREATE (m)-[COPY OF r]->(n) 
    |RETURN GRAPH""".stripMargin).graph

The CREATE keyword takes a pattern. Every node variable used in that pattern, that is already bound, is merged into the new graph, i.e. there will be exactly one instance of that node in the resulting graph. It is currently not allowed to merge relationships (because we would have to make sure that they are merged with their respective start and end nodes). Instead you can use the COPY OF keyword to create a copy of any bound relationship (copies type and properties).

We are currently working on a more comprehensive documentation. Meanwhile you can find lots of examples describing the CAPS specific Cypher syntax and our API at the examples folder: https://github.com/opencypher/cypher-for-apache-spark/tree/master/spark-cypher-examples