Can create composite index in Core API

community/kernel/src/main/java/org/neo4j/kernel/impl/api/index/MultipleIndexPopulator.java

@@ -53,7 +53,6 @@
 import org.neo4j.unsafe.impl.internal.dragons.FeatureToggles;
 
 import static java.lang.String.format;
-
 import static org.neo4j.collection.primitive.PrimitiveIntCollections.contains;
 import static org.neo4j.kernel.impl.api.index.IndexPopulationFailure.failure;
 
@@ -310,10 +309,13 @@ public void flipAfterPopulation()
 
     private int[] propertyKeyIds()
     {
-        return populations.stream()
-                .flatMapToInt( population ->
-                        IntStream.of( population.descriptor.schema().getPropertyIds() ) )
-                .toArray();
+        return populations.stream().flatMapToInt( this::propertyKeyIds ).distinct().toArray();
+    }
+
+    private IntStream propertyKeyIds( IndexPopulation population )
+    {
+        NewIndexDescriptor desc = population.descriptor;
+        return IntStream.of( desc.schema().getPropertyIds() );
     }
 
     private int[] labelIds()

community/kernel/src/main/java/org/neo4j/kernel/impl/coreapi/schema/IndexCreatorImpl.java

@@ -21,6 +21,7 @@
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 
 import org.neo4j.graphdb.ConstraintViolationException;
 import org.neo4j.graphdb.Label;
@@ -54,14 +55,7 @@ private IndexCreatorImpl( InternalSchemaActions actions, Label label, Collection
     public IndexCreator on( String propertyKey )
     {
         assertInUnterminatedTransaction();
-
-        if ( !propertyKeys.isEmpty() )
-            throw new UnsupportedOperationException(
-                    "Compound indexes are not yet supported, only one property per index is allowed." );
-
-        return
-            new IndexCreatorImpl( actions, label,
-                                  Iterables.addToCollection( asList( propertyKey ), new ArrayList<>( propertyKeys ) ) );
+        return new IndexCreatorImpl( actions, label, copyAndAdd( propertyKeys, propertyKey) );
     }
 
     @Override
@@ -79,4 +73,11 @@ protected void assertInUnterminatedTransaction()
     {
         actions.assertInOpenTransaction();
     }
+
+    private Collection<String> copyAndAdd( Collection<String> propertyKeys, String propertyKey )
+    {
+        Collection<String> ret = new ArrayList<>( propertyKeys );
+        ret.add( propertyKey );
+        return ret;
+    }
 }

community/kernel/src/test/java/org/neo4j/graphdb/SchemaAcceptanceTest.java

@@ -59,6 +59,7 @@ public class SchemaAcceptanceTest
     private GraphDatabaseService db;
     private Label label = Labels.MY_LABEL;
     private String propertyKey = "my_property_key";
+    private String secondPropertyKey = "my_second_property_key";
 
     private enum Labels implements Label
     {
@@ -82,6 +83,16 @@ public void addingAnIndexingRuleShouldSucceed() throws Exception
         assertThat( getIndexes( db, label ), containsOnly( index ) );
     }
 
+    @Test
+    public void addingACompositeIndexingRuleShouldSucceed() throws Exception
+    {
+        // WHEN
+        IndexDefinition index = createIndex( db, label, propertyKey, secondPropertyKey );
+
+        // THEN
+        assertThat( getIndexes( db, label ), containsOnly( index ) );
+    }
+
     @Test
     public void addingAnIndexingRuleInNestedTxShouldSucceed() throws Exception
     {
@@ -156,25 +167,6 @@ public void shouldThrowConstraintViolationIfAskedToIndexPropertyThatIsAlreadyInd
         assertThat( caught, not( nullValue() ) );
     }
 
-    @Test
-    public void shouldThrowConstraintViolationIfAskedToCreateCompoundIndex() throws Exception
-    {
-        // WHEN
-        try ( Transaction tx = db.beginTx() )
-        {
-            Schema schema = db.schema();
-            schema.indexFor( label )
-                    .on( "my_property_key" )
-                    .on( "other_property" ).create();
-            tx.success();
-            fail( "Should not be able to create index on multiple propertyKey keys" );
-        }
-        catch ( UnsupportedOperationException e )
-        {
-            assertThat( e.getMessage(), containsString( "Compound indexes" ) );
-        }
-    }
-
     @Test
     public void shouldThrowConstraintViolationIfAskedToCreateCompoundConstraint() throws Exception
     {
@@ -293,6 +285,20 @@ public void awaitingAllIndexesComingOnlineWorks()
         }
     }
 
+    @Test
+    public void shouldPopulateIndex() throws Exception
+    {
+        // GIVEN
+        Node node = createNode( db, propertyKey, "Neo", label );
+
+        // create an index
+        IndexDefinition index = createIndex( db, label, propertyKey );
+        waitForIndex( db, index );
+
+        // THEN
+        assertThat( findNodesByLabelAndProperty( label, propertyKey, "Neo", db ), containsOnly( node ) );
+    }
+
     @Test
     public void shouldRecreateDroppedIndex() throws Exception
     {

community/kernel/src/test/java/org/neo4j/test/mockito/matcher/Neo4jMatchers.java

@@ -39,6 +39,7 @@
 import org.neo4j.graphdb.RelationshipType;
 import org.neo4j.graphdb.Transaction;
 import org.neo4j.graphdb.schema.ConstraintDefinition;
+import org.neo4j.graphdb.schema.IndexCreator;
 import org.neo4j.graphdb.schema.IndexDefinition;
 import org.neo4j.graphdb.schema.Schema;
 import org.neo4j.helpers.collection.Iterables;
@@ -618,20 +619,25 @@ public void describeTo( Description description )
         };
     }
 
-    public static IndexDefinition createIndex( GraphDatabaseService beansAPI, Label label, String property )
+    public static IndexDefinition createIndex( GraphDatabaseService beansAPI, Label label, String... property )
     {
         IndexDefinition indexDef = createIndexNoWait( beansAPI, label, property );
 
         waitForIndex( beansAPI, indexDef );
         return indexDef;
     }
 
-    public static IndexDefinition createIndexNoWait( GraphDatabaseService beansAPI, Label label, String property )
+    public static IndexDefinition createIndexNoWait( GraphDatabaseService beansAPI, Label label, String... properties )
     {
         IndexDefinition indexDef;
         try ( Transaction tx = beansAPI.beginTx() )
         {
-            indexDef = beansAPI.schema().indexFor( label ).on( property ).create();
+            IndexCreator indexCreator = beansAPI.schema().indexFor( label );
+            for ( String property : properties )
+            {
+                indexCreator = indexCreator.on( property );
+            }
+            indexDef = indexCreator.create();
             tx.success();
         }
         return indexDef;