fix

Author: pashandor789

ydb/library/yql/dq/opt/dq_opt_hypergraph_ut.cpp

@@ -351,6 +351,19 @@ Y_UNIT_TEST_SUITE(HypergraphBuild) {
         UNIT_ASSERT(HaveSameConditions(optimizedJoin, join));
     }
 
+    Y_UNIT_TEST(OneJoinManyCondsThatMayBreakTransitiveClosure) {
+        auto join = Join("A", "B", "A.DOTA=B.LOL,A.LOL=B.LOL");
+
+        auto graph = MakeJoinHypergraph<TNodeSet64>(join);
+        Cout << graph.String() << Endl;
+        for (const auto& e: graph.GetEdges()) {
+            UNIT_ASSERT(e.IsSimple());
+        }
+
+        auto optimizedJoin = Enumerate(join);
+        UNIT_ASSERT(HaveSameConditions(optimizedJoin, join));
+    }
+
     auto MakeClique(size_t size) {
         std::shared_ptr<IBaseOptimizerNode> root = Join("R0", "R1", "R0.id=R1.id");
 

ydb/library/yql/dq/opt/dq_opt_join_hypergraph.h

@@ -513,7 +513,7 @@ class TTransitiveClosureConstructor {
             for (size_t j = 0; j < i; ++j) {
                 auto iGroup = connectedComponents.CanonicSetElement(i);
                 auto jGroup = connectedComponents.CanonicSetElement(j);
-                if (iGroup == jGroup) {
+                if (iGroup == jGroup && joinCondById[i].RelName != joinCondById[j].RelName) {
                     auto iNode = Graph_.GetNodesByRelNames({joinCondById[i].RelName});
                     auto jNode = Graph_.GetNodesByRelNames({joinCondById[j].RelName});