*: remove useless code. (pingcap#2457)

executor/executor_write.go

@@ -1170,11 +1170,8 @@ func (e *UpdateExec) fetchRows() error {
 		}
 		data := make([]types.Datum, e.SelectExec.Schema().Len())
 		newData := make([]types.Datum, e.SelectExec.Schema().Len())
-		for i, s := range e.SelectExec.Schema().Columns {
-			data[i], err = s.Eval(row.Data, e.ctx)
-			if err != nil {
-				return errors.Trace(err)
-			}
+		for i := range e.SelectExec.Schema().Columns {
+			data[i] = row.Data[i]
 			newData[i] = data[i]
 			if e.OrderedList[i] != nil {
 				val, err := e.OrderedList[i].Expr.Eval(row.Data, e.ctx)

expression/schema.go

@@ -93,13 +93,6 @@ func (s Schema) FindColumn(astCol *ast.ColumnName) (*Column, error) {
 	return s.Columns[idx], nil
 }
 
-// InitColumnIndices sets indices for columns in schema.
-func (s Schema) InitColumnIndices() {
-	for i, c := range s.Columns {
-		c.Index = i
-	}
-}
-
 // RetrieveColumn retrieves column in expression from the columns in schema.
 func (s Schema) RetrieveColumn(col *Column) *Column {
 	index := s.GetColumnIndex(col)

plan/column_pruning.go

@@ -63,7 +63,6 @@ func (p *Projection) PruneColumns(parentUsedCols []*expression.Column) {
 		selfUsedCols = append(selfUsedCols, expression.ExtractColumns(expr)...)
 	}
 	child.PruneColumns(selfUsedCols)
-	p.schema.InitColumnIndices()
 }
 
 // PruneColumns implements LogicalPlan interface.
@@ -96,7 +95,6 @@ func (p *Aggregation) PruneColumns(parentUsedCols []*expression.Column) {
 		selfUsedCols = append(selfUsedCols, expression.ExtractColumns(expr)...)
 	}
 	child.PruneColumns(selfUsedCols)
-	p.schema.InitColumnIndices()
 }
 
 // PruneColumns implements LogicalPlan interface.
@@ -128,7 +126,6 @@ func (p *Union) PruneColumns(parentUsedCols []*expression.Column) {
 		}
 		child.PruneColumns(newCols)
 	}
-	p.schema.InitColumnIndices()
 }
 
 // PruneColumns implements LogicalPlan interface.
@@ -140,7 +137,6 @@ func (p *DataSource) PruneColumns(parentUsedCols []*expression.Column) {
 			p.Columns = append(p.Columns[:i], p.Columns[i+1:]...)
 		}
 	}
-	p.schema.InitColumnIndices()
 }
 
 // PruneColumns implements LogicalPlan interface.
@@ -208,7 +204,6 @@ func (p *Join) PruneColumns(parentUsedCols []*expression.Column) {
 	} else {
 		p.schema = composedSchema
 	}
-	p.schema.InitColumnIndices()
 }
 
 // PruneColumns implements LogicalPlan interface.
@@ -246,7 +241,6 @@ func (p *Apply) PruneColumns(parentUsedCols []*expression.Column) {
 		p.schema = child.GetSchema().Clone()
 		p.schema.Columns = append(p.schema.Columns, existsCol)
 	}
-	p.schema.InitColumnIndices()
 }
 
 // PruneColumns implements LogicalPlan interface.

plan/logical_plan_builder.go

@@ -1123,6 +1123,7 @@ func (b *planBuilder) buildUpdateLists(list []*ast.Assignment, p LogicalPlan) ([
 		offset := schema.GetColumnIndex(col)
 		if offset == -1 {
 			b.err = errors.Trace(errors.Errorf("could not find column %s.%s", col.TblName, col.ColName))
+			return nil, nil
 		}
 		newExpr, np, err := b.rewrite(assign.Expr, p, nil, false)
 		if err != nil {

plan/plan.go

@@ -295,7 +295,6 @@ func (p *baseLogicalPlan) ResolveIndicesAndCorCols() {
 	for _, child := range p.children {
 		child.(LogicalPlan).ResolveIndicesAndCorCols()
 	}
-	p.schema.InitColumnIndices()
 }
 
 // PruneColumns implements LogicalPlan interface.

plan/resolve_indices.go

@@ -91,6 +91,7 @@ func (p *Apply) ResolveIndicesAndCorCols() {
 					Column: *childSchema.Columns[idx],
 					Data:   new(types.Datum),
 				}
+				resultCorCols[idx].Column.ResolveIndices(childSchema)
 			}
 			corCol.Data = resultCorCols[idx].Data
 		}