fix a bug where tableA join tableB failed due to index sizes

wayang-api/wayang-api-sql/src/main/java/org/apache/wayang/api/sql/calcite/converter/WayangJoinVisitor.java

@@ -67,8 +67,8 @@ Operator visit(final WayangJoin wayangRelNode) {
         // offset of the index in the right child
         final int offset = wayangRelNode.getInput(0).getRowType().getFieldCount();
 
-        final int leftKeyIndex = keys.get(0);
-        final int rightKeyIndex = keys.get(1) - offset;
+        final int leftKeyIndex = keys.get(0) < keys.get(1) ? keys.get(0) : keys.get(0) - offset;
+        final int rightKeyIndex = keys.get(0) < keys.get(1) ? keys.get(1) - offset : keys.get(1);
 
         final JoinOperator<Record, Record, Object> join = new JoinOperator<>(
                 new TransformationDescriptor<>(new JoinKeyExtractor(leftKeyIndex), Record.class, Object.class),

wayang-api/wayang-api-sql/src/test/java/org/apache/wayang/api/sql/SqlToWayangRelTest.java

@@ -114,7 +114,6 @@ public Tuple2<Collection<Record>, WayangPlan> buildCollectorAndWayangPlan(final
     @Test
     public void javaJoinTest() throws Exception {
         final SqlContext sqlContext = this.createSqlContext("/data/largeLeftTableIndex.csv");
-        // SELECT acc.location, count(*) FROM postgres.site
         final Tuple2<Collection<Record>, WayangPlan> t = this.buildCollectorAndWayangPlan(sqlContext,
                 "SELECT * FROM fs.largeLeftTableIndex JOIN fs.exampleRefToRef ON largeLeftTableIndex.NAMEA = exampleRefToRef.NAMEA");
         final Collection<Record> result = t.field0;
@@ -127,14 +126,12 @@ public void javaJoinTest() throws Exception {
 
         sqlContext.execute(wayangPlan);
 
-        final Record rec = result.stream().findFirst().get();
-        assert (rec.equals(new Record("test1", "test1", "test2", "test1", "test1")));
+        assert (result.stream().anyMatch(rec -> rec.equals(new Record("test1", "test1", "test2", "test1", "test1"))));
     }
 
     @Test
     public void javaMultiConditionJoin() throws Exception {
         final SqlContext sqlContext = this.createSqlContext("/data/largeLeftTableIndex.csv");
-        // SELECT acc.location, count(*) FROM postgres.site
         final Tuple2<Collection<Record>, WayangPlan> t = this.buildCollectorAndWayangPlan(sqlContext,
                 "SELECT * FROM fs.largeLeftTableIndex JOIN fs.exampleRefToRef ON largeLeftTableIndex.NAMEB = exampleRefToRef.NAMEB AND largeLeftTableIndex.NAMEC = exampleRefToRef.NAMEB");
         final Collection<Record> result = t.field0;
@@ -156,7 +153,6 @@ public void javaMultiConditionJoin() throws Exception {
     @Test
     public void aggregateCountInJavaWithIntegers() throws Exception {
         final SqlContext sqlContext = this.createSqlContext("/data/exampleInt.csv");
-        // SELECT acc.location, count(*) FROM postgres.site
         final Tuple2<Collection<Record>, WayangPlan> t = this.buildCollectorAndWayangPlan(sqlContext,
                 "SELECT exampleInt.NAMEC, COUNT(*) FROM fs.exampleInt GROUP BY NAMEC");
         final Collection<Record> result = t.field0;
@@ -177,7 +173,6 @@ public void aggregateCountInJavaWithIntegers() throws Exception {
     @Test
     public void aggregateCountInJava() throws Exception {
         final SqlContext sqlContext = this.createSqlContext("/data/largeLeftTableIndex.csv");
-        // SELECT acc.location, count(*) FROM postgres.site
         final Tuple2<Collection<Record>, WayangPlan> t = this.buildCollectorAndWayangPlan(sqlContext,
                 "SELECT largeLeftTableIndex.NAMEC, COUNT(*) FROM fs.largeLeftTableIndex GROUP BY NAMEC");
         final Collection<Record> result = t.field0;
@@ -222,8 +217,7 @@ public void filterIsNotValue() throws Exception {
         sqlContext.execute(wayangPlan);
 
         assert (!result.stream().anyMatch(record -> record.getField(0).equals("test1")));
-    }   
-
+    }
 
     @Test
     public void filterIsNotNull() throws Exception {
@@ -257,7 +251,7 @@ public void javaReduceBy() throws Exception {
 
         sqlContext.execute(wayangPlan);
 
-        assert (result.stream().findFirst().get().equals(new Record("item1", 2)));
+        assert (result.stream().anyMatch(rec -> rec.equals(new Record("item1", 2))));
     }
 
     @Test
@@ -316,10 +310,10 @@ public void filterWithLike() throws Exception {
         final WayangPlan wayangPlan = t.field1;
         sqlContext.execute(wayangPlan);
 
-        assert (result.stream().findFirst().get().equals(new Record("test1", "test1", "test2")));
+        assert (result.stream().anyMatch(rec -> rec.equals(new Record("test1", "test1", "test2"))));
     }
 
-    // @Test
+    @Test
     public void joinWithLargeLeftTableIndexCorrect() throws Exception {
         final SqlContext sqlContext = createSqlContext("/data/largeLeftTableIndex.csv");
 
@@ -330,18 +324,51 @@ public void joinWithLargeLeftTableIndexCorrect() throws Exception {
         final Collection<Record> result = t.field0;
         final WayangPlan wayangPlan = t.field1;
         sqlContext.execute(wayangPlan);
+
+        final List<Record> shouldBe = List.of(
+                new Record("test1", "test1", "test2", "test1", "test1", "test2"),
+                new Record("test2", ""     , "test2", ""     , "test2", "test2"),
+                new Record(""     , "test2", "test2", "test2", ""     , "test2")
+        );
+
+        final Map<Record, Integer> resultTally = result.stream()
+                .collect(Collectors.toMap(rec -> rec, rec -> 1, Integer::sum));
+        final Map<Record, Integer> shouldBeTally = shouldBe.stream()
+                .collect(Collectors.toMap(rec -> rec, rec -> 1, Integer::sum));
+
+        assert (resultTally.equals(shouldBeTally));
     }
 
-    // @Test
+    // Imagine case: l = {item1, item2}, r = {item3,item4}, j = {item1, item2,
+    // item3, item4} join on =($1,$3) would be =(item2, item4) in the join set
+    // however from the r set we need to factor in the
+    // offset, $3 -> 3 - l.size() = $1, r($1) = "item4" we cannot naively assume
+    // that it is always ordered as =(lRef,rRef), lRef < rRef.
+    // it may also be =($3,$1)
+    @Test
     public void joinWithLargeLeftTableIndexMirrorAlias() throws Exception {
         final SqlContext sqlContext = createSqlContext("/data/largeLeftTableIndex.csv");
 
         final Tuple2<Collection<Record>, WayangPlan> t = this.buildCollectorAndWayangPlan(sqlContext,
                 "SELECT * FROM fs.largeLeftTableIndex AS na INNER JOIN fs.largeLeftTableIndex AS nb ON nb.NAMEB = na.NAMEA " //
         );
+
         final Collection<Record> result = t.field0;
         final WayangPlan wayangPlan = t.field1;
         sqlContext.execute(wayangPlan);
+
+        final List<Record> shouldBe = List.of(
+                new Record("test1", "test1", "test2", "test1", "test1", "test2"),
+                new Record("test2", ""     , "test2", ""     , "test2", "test2"),
+                new Record(""     , "test2", "test2", "test2", ""     , "test2")
+        );
+
+        final Map<Record, Integer> resultTally = result.stream()
+                .collect(Collectors.toMap(rec -> rec, rec -> 1, Integer::sum));
+        final Map<Record, Integer> shouldBeTally = shouldBe.stream()
+                .collect(Collectors.toMap(rec -> rec, rec -> 1, Integer::sum));
+
+        assert (resultTally.equals(shouldBeTally));
     }
 
     @Test
@@ -356,7 +383,7 @@ public void exampleFilterTableRefToTableRef() throws Exception {
         final WayangPlan wayangPlan = t.field1;
         sqlContext.execute(wayangPlan);
 
-        assert (result.stream().findFirst().get().equals(new Record("test1", "test1")));
+        assert (result.stream().anyMatch(rec -> rec.equals(new Record("test1", "test1"))));
     }
 
     @Test