From ac990d10ff2d1d1042a68f0594489aed23a27453 Mon Sep 17 00:00:00 2001
From: Tuukka Lehtonen <tuukka.lehtonen@semantum.fi>
Date: Wed, 10 Jun 2020 21:41:27 +0300
Subject: [PATCH] Optimize ReadGraph.hasStatements(s,p) to not use
 getObjects(s,p)

Depending on the predicate asked for, hasStatements(s,p) can be
optimized to not realize the entire [object] result list created by
getObjects(s,p).

gitlab #558

Change-Id: I7be1d2000396ce6c1e4595cabaafef5db4224de9
---
 .../db/impl/graph/ReadGraphImpl.java          | 32 +++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/bundles/org.simantics.db.impl/src/org/simantics/db/impl/graph/ReadGraphImpl.java b/bundles/org.simantics.db.impl/src/org/simantics/db/impl/graph/ReadGraphImpl.java
index 614a96df3..d6a0aa9f4 100644
--- a/bundles/org.simantics.db.impl/src/org/simantics/db/impl/graph/ReadGraphImpl.java
+++ b/bundles/org.simantics.db.impl/src/org/simantics/db/impl/graph/ReadGraphImpl.java
@@ -48,6 +48,7 @@ import org.simantics.db.DevelopmentKeys;
 import org.simantics.db.ExternalValueSupport;
 import org.simantics.db.ReadGraph;
 import org.simantics.db.RelationContext;
+import org.simantics.db.RelationInfo;
 import org.simantics.db.Resource;
 import org.simantics.db.Session;
 import org.simantics.db.Statement;
@@ -1817,8 +1818,35 @@ public class ReadGraphImpl implements ReadGraph {
 
 		try {
 
-			Collection<Resource> objects = getObjects(subject, relation);
-			return !objects.isEmpty();
+			SyncReadProcedure<RelationInfo> procedure = new SyncReadProcedure<RelationInfo>();
+			processor.forRelationInfo(this, relation, procedure);
+			Collection<Resource> predicates = getPredicates(subject);
+			
+			if(procedure.result.isFinal) {
+				
+				return predicates.contains(relation);
+				
+			} else if (procedure.result.isFunctional) {
+
+				try {
+					int result = processor.getSingleObject(this, subject, relation);
+					return result != 0;
+				} catch (ManyObjectsForFunctionalRelationException e) {
+					return true;
+				} catch (DatabaseException e) {
+					throw new ServiceException(e);
+				}
+				
+			} else {
+
+				for(Resource predicate : getPredicates(subject)) {
+					if(isSubrelationOf(predicate, relation))
+						return true;
+				}
+				
+			}
+			
+			return false;
 
 		} catch (ServiceException e) {
 
-- 
2.47.1