[release-20.0] Fix Join Predicate Cleanup Bug in Route Merging (#16386)…

… (#16390)

Signed-off-by: Andres Taylor <[email protected]>
Signed-off-by: Florent Poinsard <[email protected]>
Co-authored-by: vitess-bot[bot] <108069721+vitess-bot[bot]@users.noreply.github.com>
Co-authored-by: Florent Poinsard <[email protected]>
Co-authored-by: Andres Taylor <[email protected]>

go/test/endtoend/vtgate/queries/misc/misc_test.go

@@ -114,6 +114,17 @@ func TestInvalidDateTimeTimestampVals(t *testing.T) {
 	require.Error(t, err)
 }
 
+func TestJoinWithThreeTables(t *testing.T) {
+	utils.SkipIfBinaryIsBelowVersion(t, 20, "vtgate")
+
+	mcmp, closer := start(t)
+	defer closer()
+
+	mcmp.Exec("insert into t1(id1, id2) values (0,0), (1,1), (2,2)")
+	mcmp.Exec("insert into tbl(id, unq_col, nonunq_col) values (0,0,0), (1,1,1), (2,2,1)")
+	mcmp.Exec("select 42 from t1 u1, t1 u2, tbl u3 where u1.id1 = u2.id1 and u1.id1 = u3.id and (u1.id2 or u2.id2 or u3.unq_col)")
+}
+
 // TestIntervalWithMathFunctions tests that the Interval keyword can be used with math functions.
 func TestIntervalWithMathFunctions(t *testing.T) {
 	mcmp, closer := start(t)

go/vt/vtgate/planbuilder/operators/SQL_builder.go

@@ -233,7 +233,9 @@ func (qb *queryBuilder) joinWith(other *queryBuilder, onCondition sqlparser.Expr
 	switch joinType {
 	case sqlparser.NormalJoinType:
 		newFromClause = append(stmt.GetFrom(), otherStmt.GetFrom()...)
-		qb.addPredicate(onCondition)
+		for _, pred := range sqlparser.SplitAndExpression(nil, onCondition) {
+			qb.addPredicate(pred)
+		}
 	default:
 		newFromClause = []sqlparser.TableExpr{buildJoin(stmt, otherStmt, onCondition, joinType)}
 	}

go/vt/vtgate/planbuilder/testdata/from_cases.json

@@ -1783,6 +1783,30 @@
       ]
     }
   },
+  {
+    "comment": "three table join with join predicate touching all tables",
+    "query": "select 42 from user u join user_extra ue on u.id = ue.user_id join music m on m.user_id = u.id where u.foo or m.foo or ue.foo",
+    "plan": {
+      "QueryType": "SELECT",
+      "Original": "select 42 from user u join user_extra ue on u.id = ue.user_id join music m on m.user_id = u.id where u.foo or m.foo or ue.foo",
+      "Instructions": {
+        "OperatorType": "Route",
+        "Variant": "Scatter",
+        "Keyspace": {
+          "Name": "user",
+          "Sharded": true
+        },
+        "FieldQuery": "select 42 from `user` as u, user_extra as ue, music as m where 1 != 1",
+        "Query": "select 42 from `user` as u, user_extra as ue, music as m where u.id = ue.user_id and m.user_id = u.id and (u.foo or m.foo or ue.foo)",
+        "Table": "`user`, music, user_extra"
+      },
+      "TablesUsed": [
+        "user.music",
+        "user.user",
+        "user.user_extra"
+      ]
+    }
+  },
   {
     "comment": "join of normal table with information_schema",
     "query": "select unsharded.foo from unsharded join information_schema.CHARACTER_SETS",