46 lines
1.6 KiB
Go
46 lines
1.6 KiB
Go
// Copyright 2015 PingCAP, Inc.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package plan
|
|
|
|
import (
|
|
"github.com/pingcap/tidb/context"
|
|
"github.com/pingcap/tidb/expression"
|
|
"github.com/pingcap/tidb/field"
|
|
"github.com/pingcap/tidb/util/format"
|
|
)
|
|
|
|
// RowIterFunc is the callback for iterating records.
|
|
type RowIterFunc func(id interface{}, data []interface{}) (more bool, err error)
|
|
|
|
// Plan is the interface of query execution plan.
|
|
type Plan interface {
|
|
// Do iterates records and applies plan logic to the result set.
|
|
// TODO: only get id or some fields.
|
|
Do(ctx context.Context, f RowIterFunc) error
|
|
// Explain the plan.
|
|
Explain(w format.Formatter)
|
|
// GetFields returns the result field list for a plan.
|
|
GetFields() []*field.ResultField
|
|
// Filter try to use index plan to reduce the result set.
|
|
// If index can be used, a new index plan is returned, 'filtered' is true.
|
|
// If no index can be used, the original plan is returned and 'filtered' return false.
|
|
Filter(ctx context.Context, expr expression.Expression) (p Plan, filtered bool, err error)
|
|
}
|
|
|
|
// Planner is implemented by any structure that has a Plan method.
|
|
type Planner interface {
|
|
// Plan function returns Plan.
|
|
Plan(ctx context.Context) (Plan, error)
|
|
}
|