Corrections for query and better estimate

Author: barthanssens

src/org/linkeddatafragments/datasource/JenaTDBDataSource.java

@@ -50,14 +50,18 @@ public TriplePatternFragment getFragment(Resource subject, Property predicate, R
         Model triples = ModelFactory.createDefaultModel();
         qexec.execConstruct(triples);
 
-        // For now, fake the estimate
+        // Try to get an estimate
         long size = triples.size();
-        long estimate = (size == limit) ? offset + limit + 1 : offset + size;
-        // Try to get a better estimate
+        long estimate = -1;
+
         GraphStatisticsHandler stats = model.getGraph().getStatisticsHandler();
         if (stats != null) {
             estimate = stats.getStatistic(subject.asNode(), predicate.asNode(), object.asNode());
         }
+        // No estimate or incorrect
+        if (estimate < offset + size) {
+            estimate = (size == limit) ? offset + size + 1 : offset + size;
+        }
 
         tdb.end();