Integrate public as bindata optionally (#293)

* Dropped unused codekit config

* Integrated dynamic and static bindata for public

* Ignore public bindata

* Add a general generate make task

* Integrated flexible public assets into web command

* Updated vendoring, added all missiong govendor deps

* Made the linter happy with the bindata and dynamic code

* Moved public bindata definition to modules directory

* Ignoring the new bindata path now

* Updated to the new public modules import path

* Updated public bindata command and drop the new prefix

vendor/github.com/pingcap/tidb/optimizer/plan/cost.go

@@ -0,0 +1,109 @@
+// 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 (
+	"math"
+)
+
+// Pre-defined cost factors.
+const (
+	FullRangeCount   = 10000
+	HalfRangeCount   = 4000
+	MiddleRangeCount = 100
+	RowCost          = 1.0
+	IndexCost        = 2.0
+	SortCost         = 2.0
+	FilterRate       = 0.5
+)
+
+// CostEstimator estimates the cost of a plan.
+type costEstimator struct {
+}
+
+// Enter implements Visitor Enter interface.
+func (c *costEstimator) Enter(p Plan) (Plan, bool) {
+	return p, false
+}
+
+// Leave implements Visitor Leave interface.
+func (c *costEstimator) Leave(p Plan) (Plan, bool) {
+	switch v := p.(type) {
+	case *IndexScan:
+		c.indexScan(v)
+	case *Limit:
+		v.rowCount = v.Src().RowCount()
+		v.startupCost = v.Src().StartupCost()
+		v.totalCost = v.Src().TotalCost()
+	case *SelectFields:
+		if v.Src() != nil {
+			v.startupCost = v.Src().StartupCost()
+			v.rowCount = v.Src().RowCount()
+			v.totalCost = v.Src().TotalCost()
+		}
+	case *SelectLock:
+		v.startupCost = v.Src().StartupCost()
+		v.rowCount = v.Src().RowCount()
+		v.totalCost = v.Src().TotalCost()
+	case *Sort:
+		// Sort plan must retrieve all the rows before returns the first row.
+		v.startupCost = v.Src().TotalCost() + v.Src().RowCount()*SortCost
+		if v.limit == 0 {
+			v.rowCount = v.Src().RowCount()
+		} else {
+			v.rowCount = math.Min(v.Src().RowCount(), v.limit)
+		}
+		v.totalCost = v.startupCost + v.rowCount*RowCost
+	case *TableScan:
+		c.tableScan(v)
+	}
+	return p, true
+}
+
+func (c *costEstimator) tableScan(v *TableScan) {
+	var rowCount float64 = FullRangeCount
+	for _, con := range v.AccessConditions {
+		rowCount *= guesstimateFilterRate(con)
+	}
+	v.startupCost = 0
+	if v.limit == 0 {
+		// limit is zero means no limit.
+		v.rowCount = rowCount
+	} else {
+		v.rowCount = math.Min(rowCount, v.limit)
+	}
+	v.totalCost = v.rowCount * RowCost
+}
+
+func (c *costEstimator) indexScan(v *IndexScan) {
+	var rowCount float64 = FullRangeCount
+	for _, con := range v.AccessConditions {
+		rowCount *= guesstimateFilterRate(con)
+	}
+	v.startupCost = 0
+	if v.limit == 0 {
+		// limit is zero means no limit.
+		v.rowCount = rowCount
+	} else {
+		v.rowCount = math.Min(rowCount, v.limit)
+	}
+	v.totalCost = v.rowCount * RowCost
+}
+
+// EstimateCost estimates the cost of the plan.
+func EstimateCost(p Plan) float64 {
+	var estimator costEstimator
+	p.Accept(&estimator)
+	return p.TotalCost()
+}