Merge pull request ldbc#338 from ldbc/cypher-path-query-opt

Cypher path query optimizations

Author: GLaDAP

.circleci/config.yml

@@ -9,7 +9,7 @@ workflows:
 
 jobs:
   test:
-    resource_class: large
+    resource_class: xlarge
     machine:
       image: ubuntu-2204:2022.04.1
     steps:

cypher/queries/interactive-complex-13.cypher

@@ -5,7 +5,7 @@
   8796093022357 AS person2Id
 }
 */
-OPTIONAL MATCH // the 'OPTIONAL' modifier can be deleted if the parameter curation ensures that both person1 and person2 exist
+MATCH
     (person1:Person {id: $person1Id}),
     (person2:Person {id: $person2Id})
 OPTIONAL MATCH

cypher/queries/interactive-complex-14.cypher

@@ -13,6 +13,17 @@ YIELD graphName
 WITH count(*) AS dummy
 // ----------------------------------------------------------------------------------------------------
 
+// Check whether a path exists -- if there is no path, the query will return an empty result
+MATCH
+    path = shortestPath((person1 {id: $person1Id})-[:KNOWS*]-(person2 {id: $person2Id}))
+
+// ----------------------------------------------------------------------------------------------------
+// the actual values are not important,
+// we are only interested in whether there is a row or not
+WITH 42 AS dummy
+// ----------------------------------------------------------------------------------------------------
+
+MATCH (person1:Person {id: $person1Id}), (person2:Person {id: $person2Id})
 CALL gds.graph.project.cypher(
   'q14graph',
   'MATCH (p:Person) RETURN id(p) AS id',
@@ -32,10 +43,9 @@ CALL gds.graph.project.cypher(
 YIELD graphName
 
 // ----------------------------------------------------------------------------------------------------
-WITH count(*) AS dummy
+WITH person1, person2
 // ----------------------------------------------------------------------------------------------------
 
-MATCH (person1:Person {id: $person1Id}), (person2:Person {id: $person2Id})
 CALL gds.shortestPath.dijkstra.stream(
     'q14graph', {sourceNode: person1, targetNode: person2, relationshipWeightProperty: 'weight'}
 )