[GitHub] [calcite] rkondakov commented on a change in pull request #1953: [CALCITE-3896] Top down trait request

[GitBox <gi...@apache.org>]

rkondakov commented on a change in pull request #1953:
URL: https://github.com/apache/calcite/pull/1953#discussion_r421854785



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File path: core/src/test/java/org/apache/calcite/tools/PlannerTest.java
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@@ -1030,10 +1030,12 @@ private void checkJoinNWay(int n) throws Exception {
         + "EnumerableProject(empid=[$2], deptno=[$3], name=[$4], salary=[$5], commission=[$6], deptno0=[$7], name0=[$8], employees=[$9], location=[ROW($10, $11)], empid0=[$0], name1=[$1])\n"
         + "  EnumerableHashJoin(condition=[=($0, $2)], joinType=[left])\n"
         + "    EnumerableTableScan(table=[[hr, dependents]])\n"
-        + "    EnumerableHashJoin(condition=[=($1, $5)], joinType=[inner])\n"
-        + "      EnumerableTableScan(table=[[hr, emps]])\n"
-        + "      EnumerableProject(deptno=[$0], name=[$1], employees=[$2], x=[$3.x], y=[$3.y])\n"
-        + "        EnumerableTableScan(table=[[hr, depts]])";
+        + "    EnumerableMergeJoin(condition=[=($1, $5)], joinType=[inner])\n"

Review comment:
       Why hash join is switched to merge join? It looks a bit weird because inputs are not sorted and we have to sort them explicitly which is a heavy task. Can it be a sign of some bug?




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