Planner Bug: Joins inside derived table (#14974)

Signed-off-by: Andres Taylor <andres@planetscale.com>
Signed-off-by: Florent Poinsard <florent.poinsard@outlook.fr>
Signed-off-by: Andrés Taylor <andres@taylor.se>
Co-authored-by: Florent Poinsard <florent.poinsard@outlook.fr>
Co-authored-by: Florent Poinsard <35779988+frouioui@users.noreply.github.com>

go/test/endtoend/vtgate/queries/subquery/subquery_test.go

@@ -116,7 +116,6 @@ func TestSubqueryInINClause(t *testing.T) {
 }
 
 func TestSubqueryInUpdate(t *testing.T) {
-	utils.SkipIfBinaryIsBelowVersion(t, 14, "vtgate")
 	mcmp, closer := start(t)
 	defer closer()
 
@@ -131,7 +130,6 @@ func TestSubqueryInUpdate(t *testing.T) {
 }
 
 func TestSubqueryInReference(t *testing.T) {
-	utils.SkipIfBinaryIsBelowVersion(t, 14, "vtgate")
 	mcmp, closer := start(t)
 	defer closer()
 
@@ -177,3 +175,16 @@ func TestSubqueryInAggregation(t *testing.T) {
 	// This fails as the planner adds `weight_string` method which make the query fail on MySQL.
 	// mcmp.Exec(`SELECT max((select min(id2) from t1 where t1.id1 = t.id1)) FROM t1 t`)
 }
+
+// TestSubqueryInDerivedTable tests that subqueries and derived tables
+// are handled correctly when there are joins inside the derived table
+func TestSubqueryInDerivedTable(t *testing.T) {
+	utils.SkipIfBinaryIsBelowVersion(t, 20, "vtgate")
+	mcmp, closer := start(t)
+	defer closer()
+
+	mcmp.Exec("INSERT INTO t1 (id1, id2) VALUES (1, 100), (2, 200), (3, 300), (4, 400), (5, 500);")
+	mcmp.Exec("INSERT INTO t2 (id3, id4) VALUES (10, 1), (20, 2), (30, 3), (40, 4), (50, 99)")
+	mcmp.Exec(`select t.a from (select t1.id2, t2.id3, (select id2 from t1 order by id2 limit 1) as a from t1 join t2 on t1.id1 = t2.id4) t`)
+	mcmp.Exec(`SELECT COUNT(*) FROM (SELECT DISTINCT t1.id1 FROM t1 JOIN t2 ON t1.id1 = t2.id4) dt`)
+}

go/test/endtoend/vtgate/schematracker/sharded_prs/st_sharded_test.go

@@ -209,7 +209,6 @@ func TestMain(m *testing.M) {
 
 func TestAddColumn(t *testing.T) {
 	defer cluster.PanicHandler(t)
-	utils.SkipIfBinaryIsBelowVersion(t, 14, "vtgate")
 	ctx := context.Background()
 	conn, err := mysql.Connect(ctx, &vtParams)
 	require.NoError(t, err)

go/vt/sqlparser/ast_funcs.go

@@ -429,6 +429,7 @@ func (node TableName) IsEmpty() bool {
 	// If Name is empty, Qualifier is also empty.
 	return node.Name.IsEmpty()
 }
+func (node TableName) NonEmpty() bool { return !node.Name.IsEmpty() }
 
 // NewWhere creates a WHERE or HAVING clause out
 // of a Expr. If the expression is nil, it returns nil.

go/vt/vtgate/executor_select_test.go

@@ -3914,14 +3914,14 @@ func TestSelectAggregationNoData(t *testing.T) {
 		{
 			sql:         `select count(*) from (select col1, col2 from user limit 2) x`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col1|col2|1", "int64|int64|int64")),
-			expSandboxQ: "select col1, col2, 1 from (select col1, col2 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col1, x.col2, 1 from (select col1, col2 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"count(*)" type:INT64]`,
 			expRow:      `[[INT64(0)]]`,
 		},
 		{
 			sql:         `select col2, count(*) from (select col1, col2 from user limit 2) x group by col2`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col1|col2|1|weight_string(col2)", "int64|int64|int64|varbinary")),
-			expSandboxQ: "select col1, col2, 1, weight_string(col2) from (select col1, col2 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col1, x.col2, 1, weight_string(x.col2) from (select col1, col2 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"col2" type:INT64 name:"count(*)" type:INT64]`,
 			expRow:      `[]`,
 		},
@@ -4006,70 +4006,70 @@ func TestSelectAggregationData(t *testing.T) {
 		{
 			sql:         `select count(*) from (select col1, col2 from user limit 2) x`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col1|col2|1", "int64|int64|int64"), "100|200|1", "200|300|1"),
-			expSandboxQ: "select col1, col2, 1 from (select col1, col2 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col1, x.col2, 1 from (select col1, col2 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"count(*)" type:INT64]`,
 			expRow:      `[[INT64(2)]]`,
 		},
 		{
 			sql:         `select col2, count(*) from (select col1, col2 from user limit 9) x group by col2`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col1|col2|1|weight_string(col2)", "int64|int64|int64|varbinary"), "100|3|1|NULL", "200|2|1|NULL"),
-			expSandboxQ: "select col1, col2, 1, weight_string(col2) from (select col1, col2 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col1, x.col2, 1, weight_string(x.col2) from (select col1, col2 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"col2" type:INT64 name:"count(*)" type:INT64]`,
 			expRow:      `[[INT64(2) INT64(4)] [INT64(3) INT64(5)]]`,
 		},
 		{
 			sql:         `select count(col1) from (select id, col1 from user limit 2) x`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("id|col1", "int64|varchar"), "1|a", "2|b"),
-			expSandboxQ: "select id, col1 from (select id, col1 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.id, x.col1 from (select id, col1 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"count(col1)" type:INT64]`,
 			expRow:      `[[INT64(2)]]`,
 		},
 		{
 			sql:         `select count(col1), col2 from (select col2, col1 from user limit 9) x group by col2`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col2|col1|weight_string(col2)", "int64|varchar|varbinary"), "3|a|NULL", "2|b|NULL"),
-			expSandboxQ: "select col2, col1, weight_string(col2) from (select col2, col1 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col2, x.col1, weight_string(x.col2) from (select col2, col1 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"count(col1)" type:INT64 name:"col2" type:INT64]`,
 			expRow:      `[[INT64(4) INT64(2)] [INT64(5) INT64(3)]]`,
 		},
 		{
 			sql:         `select col1, count(col2) from (select col1, col2 from user limit 9) x group by col1`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col1|col2|weight_string(col1)", "varchar|int64|varbinary"), "a|1|a", "b|null|b"),
-			expSandboxQ: "select col1, col2, weight_string(col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col1, x.col2, weight_string(x.col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"col1" type:VARCHAR name:"count(col2)" type:INT64]`,
 			expRow:      `[[VARCHAR("a") INT64(5)] [VARCHAR("b") INT64(0)]]`,
 		},
 		{
 			sql:         `select col1, count(col2) from (select col1, col2 from user limit 32) x group by col1`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col1|col2|weight_string(col1)", "varchar|int64|varbinary"), "null|1|null", "null|null|null", "a|1|a", "b|null|b"),
-			expSandboxQ: "select col1, col2, weight_string(col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col1, x.col2, weight_string(x.col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"col1" type:VARCHAR name:"count(col2)" type:INT64]`,
 			expRow:      `[[NULL INT64(8)] [VARCHAR("a") INT64(8)] [VARCHAR("b") INT64(0)]]`,
 		},
 		{
 			sql:         `select col1, sum(col2) from (select col1, col2 from user limit 4) x group by col1`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col1|col2|weight_string(col1)", "varchar|int64|varbinary"), "a|3|a"),
-			expSandboxQ: "select col1, col2, weight_string(col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col1, x.col2, weight_string(x.col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"col1" type:VARCHAR name:"sum(col2)" type:DECIMAL]`,
 			expRow:      `[[VARCHAR("a") DECIMAL(12)]]`,
 		},
 		{
 			sql:         `select col1, sum(col2) from (select col1, col2 from user limit 4) x group by col1`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col1|col2|weight_string(col1)", "varchar|varchar|varbinary"), "a|2|a"),
-			expSandboxQ: "select col1, col2, weight_string(col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col1, x.col2, weight_string(x.col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"col1" type:VARCHAR name:"sum(col2)" type:FLOAT64]`,
 			expRow:      `[[VARCHAR("a") FLOAT64(8)]]`,
 		},
 		{
 			sql:         `select col1, sum(col2) from (select col1, col2 from user limit 4) x group by col1`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col1|col2|weight_string(col1)", "varchar|varchar|varbinary"), "a|x|a"),
-			expSandboxQ: "select col1, col2, weight_string(col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col1, x.col2, weight_string(x.col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"col1" type:VARCHAR name:"sum(col2)" type:FLOAT64]`,
 			expRow:      `[[VARCHAR("a") FLOAT64(0)]]`,
 		},
 		{
 			sql:         `select col1, sum(col2) from (select col1, col2 from user limit 4) x group by col1`,
 			sandboxRes:  sqltypes.MakeTestResult(sqltypes.MakeTestFields("col1|col2|weight_string(col1)", "varchar|varchar|varbinary"), "a|null|a"),
-			expSandboxQ: "select col1, col2, weight_string(col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
+			expSandboxQ: "select x.col1, x.col2, weight_string(x.col1) from (select col1, col2 from `user`) as x limit :__upper_limit",
 			expField:    `[name:"col1" type:VARCHAR name:"sum(col2)" type:FLOAT64]`,
 			expRow:      `[[VARCHAR("a") NULL]]`,
 		},

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

@@ -21,6 +21,7 @@ import (
 	"slices"
 	"sort"
 
+	"vitess.io/vitess/go/slice"
 	"vitess.io/vitess/go/vt/sqlparser"
 	"vitess.io/vitess/go/vt/vterrors"
 	"vitess.io/vitess/go/vt/vtgate/planbuilder/plancontext"
@@ -84,7 +85,7 @@ func (qb *queryBuilder) addTableExpr(
 }
 
 func (qb *queryBuilder) addPredicate(expr sqlparser.Expr) {
-	if _, toBeSkipped := qb.ctx.SkipPredicates[expr]; toBeSkipped {
+	if qb.ctx.ShouldSkip(expr) {
 		// This is a predicate that was added to the RHS of an ApplyJoin.
 		// The original predicate will be added, so we don't have to add this here
 		return
@@ -523,20 +524,24 @@ func buildProjection(op *Projection, qb *queryBuilder) {
 }
 
 func buildApplyJoin(op *ApplyJoin, qb *queryBuilder) {
+	predicates := slice.Map(op.JoinPredicates.columns, func(jc applyJoinColumn) sqlparser.Expr {
+		// since we are adding these join predicates, we need to mark to broken up version (RHSExpr) of it as done
+		err := qb.ctx.SkipJoinPredicates(jc.Original)
+		if err != nil {
+			panic(err)
+		}
+		return jc.Original
+	})
+	pred := sqlparser.AndExpressions(predicates...)
+
 	buildQuery(op.LHS, qb)
-	// If we are going to add the predicate used in join here
-	// We should not add the predicate's copy of when it was split into
-	// two parts. To avoid this, we use the SkipPredicates map.
-	for _, expr := range qb.ctx.JoinPredicates[op.Predicate] {
-		qb.ctx.SkipPredicates[expr] = nil
-	}
+
 	qbR := &queryBuilder{ctx: qb.ctx}
 	buildQuery(op.RHS, qbR)
-
 	if op.LeftJoin {
-		qb.joinOuterWith(qbR, op.Predicate)
+		qb.joinOuterWith(qbR, pred)
 	} else {
-		qb.joinInnerWith(qbR, op.Predicate)
+		qb.joinInnerWith(qbR, pred)
 	}
 }
 

go/vt/vtgate/planbuilder/operators/aggregator.go

@@ -120,6 +120,14 @@ func (a *Aggregator) isDerived() bool {
 	return a.DT != nil
 }
 
+func (a *Aggregator) derivedName() string {
+	if a.DT == nil {
+		return ""
+	}
+
+	return a.DT.Alias
+}
+
 func (a *Aggregator) FindCol(ctx *plancontext.PlanningContext, in sqlparser.Expr, underRoute bool) int {
 	if underRoute && a.isDerived() {
 		// We don't want to use columns on this operator if it's a derived table under a route.

go/vt/vtgate/planbuilder/operators/apply_join.go

@@ -37,9 +37,6 @@ type (
 		// LeftJoin will be true in the case of an outer join
 		LeftJoin bool
 
-		// Before offset planning
-		Predicate sqlparser.Expr
-
 		// JoinColumns keeps track of what AST expression is represented in the Columns array
 		JoinColumns *applyJoinColumns
 
@@ -85,16 +82,17 @@ type (
 	}
 )
 
-func NewApplyJoin(lhs, rhs Operator, predicate sqlparser.Expr, leftOuterJoin bool) *ApplyJoin {
-	return &ApplyJoin{
+func NewApplyJoin(ctx *plancontext.PlanningContext, lhs, rhs Operator, predicate sqlparser.Expr, leftOuterJoin bool) *ApplyJoin {
+	aj := &ApplyJoin{
 		LHS:            lhs,
 		RHS:            rhs,
 		Vars:           map[string]int{},
-		Predicate:      predicate,
 		LeftJoin:       leftOuterJoin,
 		JoinColumns:    &applyJoinColumns{},
 		JoinPredicates: &applyJoinColumns{},
 	}
+	aj.AddJoinPredicate(ctx, predicate)
+	return aj
 }
 
 // Clone implements the Operator interface
@@ -106,7 +104,6 @@ func (aj *ApplyJoin) Clone(inputs []Operator) Operator {
 	kopy.JoinColumns = aj.JoinColumns.clone()
 	kopy.JoinPredicates = aj.JoinPredicates.clone()
 	kopy.Vars = maps.Clone(aj.Vars)
-	kopy.Predicate = sqlparser.CloneExpr(aj.Predicate)
 	kopy.ExtraLHSVars = slices.Clone(aj.ExtraLHSVars)
 	return &kopy
 }
@@ -150,8 +147,9 @@ func (aj *ApplyJoin) IsInner() bool {
 }
 
 func (aj *ApplyJoin) AddJoinPredicate(ctx *plancontext.PlanningContext, expr sqlparser.Expr) {
-	aj.Predicate = ctx.SemTable.AndExpressions(expr, aj.Predicate)
-
+	if expr == nil {
+		return
+	}
 	col := breakExpressionInLHSandRHSForApplyJoin(ctx, expr, TableID(aj.LHS))
 	aj.JoinPredicates.add(col)
 	rhs := aj.RHS.AddPredicate(ctx, col.RHSExpr)
@@ -266,11 +264,14 @@ func (aj *ApplyJoin) addOffset(offset int) {
 }
 
 func (aj *ApplyJoin) ShortDescription() string {
-	pred := sqlparser.String(aj.Predicate)
-	columns := slice.Map(aj.JoinColumns.columns, func(from applyJoinColumn) string {
-		return sqlparser.String(from.Original)
-	})
-	firstPart := fmt.Sprintf("on %s columns: %s", pred, strings.Join(columns, ", "))
+	fn := func(cols *applyJoinColumns) string {
+		out := slice.Map(cols.columns, func(jc applyJoinColumn) string {
+			return jc.String()
+		})
+		return strings.Join(out, ", ")
+	}
+
+	firstPart := fmt.Sprintf("on %s columns: %s", fn(aj.JoinPredicates), fn(aj.JoinColumns))
 	if len(aj.ExtraLHSVars) == 0 {
 		return firstPart
 	}
@@ -361,6 +362,14 @@ func (a *ApplyJoin) LHSColumnsNeeded(ctx *plancontext.PlanningContext) (needed s
 	return ctx.SemTable.Uniquify(needed)
 }
 
+func (jc applyJoinColumn) String() string {
+	rhs := sqlparser.String(jc.RHSExpr)
+	lhs := slice.Map(jc.LHSExprs, func(e BindVarExpr) string {
+		return sqlparser.String(e.Expr)
+	})
+	return fmt.Sprintf("[%s | %s | %s]", strings.Join(lhs, ", "), rhs, sqlparser.String(jc.Original))
+}
+
 func (jc applyJoinColumn) IsPureLeft() bool {
 	return jc.RHSExpr == nil
 }

go/vt/vtgate/planbuilder/operators/ast_to_op.go

@@ -196,6 +196,10 @@ func createOpFromStmt(inCtx *plancontext.PlanningContext, stmt sqlparser.Stateme
 	if err != nil {
 		panic(err)
 	}
+
+	// need to remember which predicates have been broken up during join planning
+	inCtx.KeepPredicateInfo(ctx)
+
 	return op
 }
 

go/vt/vtgate/planbuilder/operators/expressions.go

@@ -51,7 +51,8 @@ func breakExpressionInLHSandRHSForApplyJoin(
 		cursor.Replace(arg)
 	}, nil).(sqlparser.Expr)
 
-	ctx.JoinPredicates[expr] = append(ctx.JoinPredicates[expr], rewrittenExpr)
+	ctx.AddJoinPredicates(expr, rewrittenExpr)
 	col.RHSExpr = rewrittenExpr
+	col.Original = expr
 	return
 }

go/vt/vtgate/planbuilder/operators/join_merging.go

@@ -203,7 +203,7 @@ func mergeShardedRouting(r1 *ShardedRouting, r2 *ShardedRouting) *ShardedRouting
 }
 
 func (jm *joinMerger) getApplyJoin(ctx *plancontext.PlanningContext, op1, op2 *Route) *ApplyJoin {
-	return NewApplyJoin(op1.Source, op2.Source, ctx.SemTable.AndExpressions(jm.predicates...), !jm.innerJoin)
+	return NewApplyJoin(ctx, op1.Source, op2.Source, ctx.SemTable.AndExpressions(jm.predicates...), !jm.innerJoin)
 }
 
 func (jm *joinMerger) merge(ctx *plancontext.PlanningContext, op1, op2 *Route, r Routing) *Route {

go/vt/vtgate/planbuilder/operators/offset_planning.go

@@ -28,6 +28,7 @@ import (
 // planOffsets will walk the tree top down, adding offset information to columns in the tree for use in further optimization,
 func planOffsets(ctx *plancontext.PlanningContext, root Operator) Operator {
 	type offsettable interface {
+		Operator
 		planOffsets(ctx *plancontext.PlanningContext) Operator
 	}
 
@@ -37,9 +38,16 @@ func planOffsets(ctx *plancontext.PlanningContext, root Operator) Operator {
 			panic(vterrors.VT13001(fmt.Sprintf("should not see %T here", in)))
 		case offsettable:
 			newOp := op.planOffsets(ctx)
-			if newOp != nil {
-				return newOp, Rewrote("new operator after offset planning")
+
+			if newOp == nil {
+				newOp = op
+			}
+
+			if DebugOperatorTree {
+				fmt.Println("Planned offsets for:")
+				fmt.Println(ToTree(newOp))
 			}
+			return newOp, nil
 		}
 		return in, NoRewrite
 	}

go/vt/vtgate/planbuilder/operators/projection.go

@@ -142,7 +142,7 @@ func (sp StarProjections) GetSelectExprs() sqlparser.SelectExprs {
 
 func (ap AliasedProjections) GetColumns() []*sqlparser.AliasedExpr {
 	return slice.Map(ap, func(from *ProjExpr) *sqlparser.AliasedExpr {
-		return aeWrap(from.ColExpr)
+		return from.Original
 	})
 }
 
@@ -229,6 +229,14 @@ func (p *Projection) isDerived() bool {
 	return p.DT != nil
 }
 
+func (p *Projection) derivedName() string {
+	if p.DT == nil {
+		return ""
+	}
+
+	return p.DT.Alias
+}
+
 func (p *Projection) FindCol(ctx *plancontext.PlanningContext, expr sqlparser.Expr, underRoute bool) int {
 	ap, err := p.GetAliasedProjections()
 	if err != nil {