planner/core: support named window (#8937)

planner/core/errors.go

@@ -54,6 +54,12 @@ const (
 	codePrivilegeCheckFail              = mysql.ErrUnknown
 	codeWindowInvalidWindowFuncUse      = mysql.ErrWindowInvalidWindowFuncUse
 	codeWindowInvalidWindowFuncAliasUse = mysql.ErrWindowInvalidWindowFuncAliasUse
+	codeWindowNoSuchWindow              = mysql.ErrWindowNoSuchWindow
+	codeWindowCircularityInWindowGraph  = mysql.ErrWindowCircularityInWindowGraph
+	codeWindowNoChildPartitioning       = mysql.ErrWindowNoChildPartitioning
+	codeWindowNoInherentFrame           = mysql.ErrWindowNoInherentFrame
+	codeWindowNoRedefineOrderBy         = mysql.ErrWindowNoRedefineOrderBy
+	codeWindowDuplicateName             = mysql.ErrWindowDuplicateName
 )
 
 // error definitions.
@@ -94,6 +100,12 @@ var (
 	ErrPrivilegeCheckFail              = terror.ClassOptimizer.New(codePrivilegeCheckFail, "privilege check fail")
 	ErrWindowInvalidWindowFuncUse      = terror.ClassOptimizer.New(codeWindowInvalidWindowFuncUse, mysql.MySQLErrName[mysql.ErrWindowInvalidWindowFuncUse])
 	ErrWindowInvalidWindowFuncAliasUse = terror.ClassOptimizer.New(codeWindowInvalidWindowFuncAliasUse, mysql.MySQLErrName[mysql.ErrWindowInvalidWindowFuncAliasUse])
+	ErrWindowNoSuchWindow              = terror.ClassOptimizer.New(codeWindowNoSuchWindow, mysql.MySQLErrName[mysql.ErrWindowNoSuchWindow])
+	ErrWindowCircularityInWindowGraph  = terror.ClassOptimizer.New(codeWindowCircularityInWindowGraph, mysql.MySQLErrName[mysql.ErrWindowCircularityInWindowGraph])
+	ErrWindowNoChildPartitioning       = terror.ClassOptimizer.New(codeWindowNoChildPartitioning, mysql.MySQLErrName[mysql.ErrWindowNoChildPartitioning])
+	ErrWindowNoInherentFrame           = terror.ClassOptimizer.New(codeWindowNoInherentFrame, mysql.MySQLErrName[mysql.ErrWindowNoInherentFrame])
+	ErrWindowNoRedefineOrderBy         = terror.ClassOptimizer.New(codeWindowNoRedefineOrderBy, mysql.MySQLErrName[mysql.ErrWindowNoRedefineOrderBy])
+	ErrWindowDuplicateName             = terror.ClassOptimizer.New(codeWindowDuplicateName, mysql.MySQLErrName[mysql.ErrWindowDuplicateName])
 )
 
 func init() {
@@ -124,6 +136,12 @@ func init() {
 
 		codeWindowInvalidWindowFuncUse:      mysql.ErrWindowInvalidWindowFuncUse,
 		codeWindowInvalidWindowFuncAliasUse: mysql.ErrWindowInvalidWindowFuncAliasUse,
+		codeWindowNoSuchWindow:              mysql.ErrWindowNoSuchWindow,
+		codeWindowCircularityInWindowGraph:  mysql.ErrWindowCircularityInWindowGraph,
+		codeWindowNoChildPartitioning:       mysql.ErrWindowNoChildPartitioning,
+		codeWindowNoInherentFrame:           mysql.ErrWindowNoInherentFrame,
+		codeWindowNoRedefineOrderBy:         mysql.ErrWindowNoRedefineOrderBy,
+		codeWindowDuplicateName:             mysql.ErrWindowDuplicateName,
 	}
 	terror.ErrClassToMySQLCodes[terror.ClassOptimizer] = mysqlErrCodeMap
 }

planner/core/logical_plan_builder.go

@@ -1878,6 +1878,11 @@ func (b *PlanBuilder) buildSelect(sel *ast.SelectStmt) (p LogicalPlan, err error
 		}
 	}
 
+	b.windowSpecs, err = buildWindowSpecs(sel.WindowSpecs)
+	if err != nil {
+		return nil, err
+	}
+
 	if hasWindowFuncField {
 		// Now we build the window function fields.
 		p, oldLen, err = b.buildProjection(p, sel.Fields.Fields, windowMap, true)
@@ -2592,6 +2597,16 @@ func (b *PlanBuilder) buildProjectionForWindow(p LogicalPlan, expr *ast.WindowFu
 
 	var items []*ast.ByItem
 	spec := expr.Spec
+	if spec.Ref.L != "" {
+		ref, ok := b.windowSpecs[spec.Ref.L]
+		if !ok {
+			return nil, nil, nil, ErrWindowNoSuchWindow.GenWithStackByArgs(spec.Ref.O)
+		}
+		err := mergeWindowSpec(&spec, &ref)
+		if err != nil {
+			return nil, nil, nil, err
+		}
+	}
 	if spec.PartitionBy != nil {
 		items = append(items, spec.PartitionBy.Items...)
 	}
@@ -2679,6 +2694,68 @@ func (b *PlanBuilder) buildWindowFunction(p LogicalPlan, expr *ast.WindowFuncExp
 	return window, nil
 }
 
+// resolveWindowSpec resolve window specifications for sql like `select ... from t window w1 as (w2), w2 as (partition by a)`.
+// We need to resolve the referenced window to get the definition of current window spec.
+func resolveWindowSpec(spec *ast.WindowSpec, specs map[string]ast.WindowSpec, inStack map[string]bool) error {
+	if inStack[spec.Name.L] {
+		return errors.Trace(ErrWindowCircularityInWindowGraph)
+	}
+	if spec.Ref.L == "" {
+		return nil
+	}
+	ref, ok := specs[spec.Ref.L]
+	if !ok {
+		return ErrWindowNoSuchWindow.GenWithStackByArgs(spec.Ref.O)
+	}
+	inStack[spec.Name.L] = true
+	err := resolveWindowSpec(&ref, specs, inStack)
+	if err != nil {
+		return err
+	}
+	inStack[spec.Name.L] = false
+	return mergeWindowSpec(spec, &ref)
+}
+
+func mergeWindowSpec(spec, ref *ast.WindowSpec) error {
+	if ref.Frame != nil {
+		return ErrWindowNoInherentFrame.GenWithStackByArgs(ref.Name.O)
+	}
+	if ref.OrderBy != nil {
+		if spec.OrderBy != nil {
+			name := spec.Name.O
+			if name == "" {
+				name = "<unnamed window>"
+			}
+			return ErrWindowNoRedefineOrderBy.GenWithStackByArgs(name, ref.Name.O)
+		}
+		spec.OrderBy = ref.OrderBy
+	}
+	if spec.PartitionBy != nil {
+		return errors.Trace(ErrWindowNoChildPartitioning)
+	}
+	spec.PartitionBy = ref.PartitionBy
+	spec.Ref = model.NewCIStr("")
+	return nil
+}
+
+func buildWindowSpecs(specs []ast.WindowSpec) (map[string]ast.WindowSpec, error) {
+	specsMap := make(map[string]ast.WindowSpec, len(specs))
+	for _, spec := range specs {
+		if _, ok := specsMap[spec.Name.L]; ok {
+			return nil, ErrWindowDuplicateName.GenWithStackByArgs(spec.Name.O)
+		}
+		specsMap[spec.Name.L] = spec
+	}
+	inStack := make(map[string]bool, len(specs))
+	for _, spec := range specs {
+		err := resolveWindowSpec(&spec, specsMap, inStack)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return specsMap, nil
+}
+
 // extractTableList extracts all the TableNames from node.
 func extractTableList(node ast.ResultSetNode, input []*ast.TableName) []*ast.TableName {
 	switch x := node.(type) {

planner/core/logical_plan_test.go

@@ -1960,6 +1960,42 @@ func (s *testPlanSuite) TestWindowFunction(c *C) {
 			sql:    "select sum(a) over() as sum_a from t group by sum_a",
 			result: "[planner:1247]Reference 'sum_a' not supported (reference to window function)",
 		},
+		{
+			sql:    "select sum(a) over() from t window w1 as (w2)",
+			result: "[planner:3579]Window name 'w2' is not defined.",
+		},
+		{
+			sql:    "select sum(a) over(w) from t",
+			result: "[planner:3579]Window name 'w' is not defined.",
+		},
+		{
+			sql:    "select sum(a) over() from t window w1 as (w2), w2 as (w1)",
+			result: "[planner:3580]There is a circularity in the window dependency graph.",
+		},
+		{
+			sql:    "select sum(a) over(w partition by a) from t window w as ()",
+			result: "[planner:3581]A window which depends on another cannot define partitioning.",
+		},
+		{
+			sql:    "select sum(a) over(w) from t window w as (rows between 1 preceding AND 1 following)",
+			result: "[planner:3582]Window 'w' has a frame definition, so cannot be referenced by another window.",
+		},
+		{
+			sql:    "select sum(a) over(w order by b) from t window w as (order by a)",
+			result: "[planner:3583]Window '<unnamed window>' cannot inherit 'w' since both contain an ORDER BY clause.",
+		},
+		{
+			sql:    "select sum(a) over() from t window w1 as (), w1 as ()",
+			result: "[planner:3591]Window 'w1' is defined twice.",
+		},
+		{
+			sql:    "select sum(a) over(w1), avg(a) over(w2) from t window w1 as (partition by a), w2 as (w1)",
+			result: "TableReader(Table(t))->Window(sum(test.t.a))->Window(avg(test.t.a))->Projection",
+		},
+		{
+			sql:    "select a from t window w1 as (partition by a) order by (sum(a) over(w1))",
+			result: "TableReader(Table(t))->Window(sum(test.t.a))->Sort->Projection",
+		},
 	}
 
 	s.Parser.EnableWindowFunc(true)

planner/core/planbuilder.go

@@ -137,6 +137,8 @@ type PlanBuilder struct {
 	// inStraightJoin represents whether the current "SELECT" statement has
 	// "STRAIGHT_JOIN" option.
 	inStraightJoin bool
+
+	windowSpecs map[string]ast.WindowSpec
 }
 
 // GetVisitInfo gets the visitInfo of the PlanBuilder.