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gitea/vendor/github.com/pingcap/tidb/optimizer/plan/planbuilder.go

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// 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/juju/errors"
"github.com/ngaut/log"
"github.com/pingcap/tidb/ast"
"github.com/pingcap/tidb/infoschema"
"github.com/pingcap/tidb/model"
"github.com/pingcap/tidb/mysql"
"github.com/pingcap/tidb/parser/opcode"
"github.com/pingcap/tidb/terror"
"github.com/pingcap/tidb/util/charset"
"github.com/pingcap/tidb/util/types"
)
// Error instances.
var (
ErrUnsupportedType = terror.ClassOptimizerPlan.New(CodeUnsupportedType, "Unsupported type")
)
// Error codes.
const (
CodeUnsupportedType terror.ErrCode = 1
)
// BuildPlan builds a plan from a node.
// It returns ErrUnsupportedType if ast.Node type is not supported yet.
func BuildPlan(node ast.Node, sb SubQueryBuilder) (Plan, error) {
builder := planBuilder{sb: sb}
p := builder.build(node)
return p, builder.err
}
// planBuilder builds Plan from an ast.Node.
// It just builds the ast node straightforwardly.
type planBuilder struct {
err error
hasAgg bool
sb SubQueryBuilder
obj interface{}
}
func (b *planBuilder) build(node ast.Node) Plan {
switch x := node.(type) {
case *ast.AdminStmt:
return b.buildAdmin(x)
case *ast.AlterTableStmt:
return b.buildDDL(x)
case *ast.CreateDatabaseStmt:
return b.buildDDL(x)
case *ast.CreateIndexStmt:
return b.buildDDL(x)
case *ast.CreateTableStmt:
return b.buildDDL(x)
case *ast.DeallocateStmt:
return &Deallocate{Name: x.Name}
case *ast.DeleteStmt:
return b.buildDelete(x)
case *ast.DropDatabaseStmt:
return b.buildDDL(x)
case *ast.DropIndexStmt:
return b.buildDDL(x)
case *ast.DropTableStmt:
return b.buildDDL(x)
case *ast.ExecuteStmt:
return &Execute{Name: x.Name, UsingVars: x.UsingVars}
case *ast.ExplainStmt:
return b.buildExplain(x)
case *ast.InsertStmt:
return b.buildInsert(x)
case *ast.PrepareStmt:
return b.buildPrepare(x)
case *ast.SelectStmt:
return b.buildSelect(x)
case *ast.UnionStmt:
return b.buildUnion(x)
case *ast.UpdateStmt:
return b.buildUpdate(x)
case *ast.UseStmt:
return b.buildSimple(x)
case *ast.SetCharsetStmt:
return b.buildSimple(x)
case *ast.SetStmt:
return b.buildSimple(x)
case *ast.ShowStmt:
return b.buildShow(x)
case *ast.DoStmt:
return b.buildSimple(x)
case *ast.BeginStmt:
return b.buildSimple(x)
case *ast.CommitStmt:
return b.buildSimple(x)
case *ast.RollbackStmt:
return b.buildSimple(x)
case *ast.CreateUserStmt:
return b.buildSimple(x)
case *ast.SetPwdStmt:
return b.buildSimple(x)
case *ast.GrantStmt:
return b.buildSimple(x)
case *ast.TruncateTableStmt:
return b.buildDDL(x)
}
b.err = ErrUnsupportedType.Gen("Unsupported type %T", node)
return nil
}
// Detect aggregate function or groupby clause.
func (b *planBuilder) detectSelectAgg(sel *ast.SelectStmt) bool {
if sel.GroupBy != nil {
return true
}
for _, f := range sel.GetResultFields() {
if ast.HasAggFlag(f.Expr) {
return true
}
}
if sel.Having != nil {
if ast.HasAggFlag(sel.Having.Expr) {
return true
}
}
if sel.OrderBy != nil {
for _, item := range sel.OrderBy.Items {
if ast.HasAggFlag(item.Expr) {
return true
}
}
}
return false
}
// extractSelectAgg extracts aggregate functions and converts ColumnNameExpr to aggregate function.
func (b *planBuilder) extractSelectAgg(sel *ast.SelectStmt) []*ast.AggregateFuncExpr {
extractor := &ast.AggregateFuncExtractor{AggFuncs: make([]*ast.AggregateFuncExpr, 0)}
for _, f := range sel.GetResultFields() {
n, ok := f.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr!")
return nil
}
ve, ok := f.Expr.(*ast.ValueExpr)
if ok && len(f.Column.Name.O) > 0 {
agg := &ast.AggregateFuncExpr{
F: ast.AggFuncFirstRow,
Args: []ast.ExprNode{ve},
}
extractor.AggFuncs = append(extractor.AggFuncs, agg)
n = agg
}
f.Expr = n.(ast.ExprNode)
}
// Extract agg funcs from having clause.
if sel.Having != nil {
n, ok := sel.Having.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr from having clause")
return nil
}
sel.Having.Expr = n.(ast.ExprNode)
}
// Extract agg funcs from orderby clause.
if sel.OrderBy != nil {
for _, item := range sel.OrderBy.Items {
n, ok := item.Expr.Accept(extractor)
if !ok {
b.err = errors.New("Failed to extract agg expr from orderby clause")
return nil
}
item.Expr = n.(ast.ExprNode)
// If item is PositionExpr, we need to rebind it.
// For PositionExpr will refer to a ResultField in fieldlist.
// After extract AggExpr from fieldlist, it may be changed (See the code above).
if pe, ok := item.Expr.(*ast.PositionExpr); ok {
pe.Refer = sel.GetResultFields()[pe.N-1]
}
}
}
return extractor.AggFuncs
}
func (b *planBuilder) buildSubquery(n ast.Node) {
sv := &subqueryVisitor{
builder: b,
}
_, ok := n.Accept(sv)
if !ok {
log.Errorf("Extract subquery error")
}
}
func (b *planBuilder) buildSelect(sel *ast.SelectStmt) Plan {
var aggFuncs []*ast.AggregateFuncExpr
hasAgg := b.detectSelectAgg(sel)
if hasAgg {
aggFuncs = b.extractSelectAgg(sel)
}
// Build subquery
// Convert subquery to expr with plan
b.buildSubquery(sel)
var p Plan
if sel.From != nil {
p = b.buildFrom(sel)
if b.err != nil {
return nil
}
if sel.LockTp != ast.SelectLockNone {
p = b.buildSelectLock(p, sel.LockTp)
if b.err != nil {
return nil
}
}
if hasAgg {
p = b.buildAggregate(p, aggFuncs, sel.GroupBy)
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
} else {
if hasAgg {
p = b.buildAggregate(p, aggFuncs, nil)
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
}
if sel.Having != nil {
p = b.buildHaving(p, sel.Having)
if b.err != nil {
return nil
}
}
if sel.Distinct {
p = b.buildDistinct(p)
if b.err != nil {
return nil
}
}
if sel.OrderBy != nil && !matchOrder(p, sel.OrderBy.Items) {
p = b.buildSort(p, sel.OrderBy.Items)
if b.err != nil {
return nil
}
}
if sel.Limit != nil {
p = b.buildLimit(p, sel.Limit)
if b.err != nil {
return nil
}
}
return p
}
func (b *planBuilder) buildFrom(sel *ast.SelectStmt) Plan {
from := sel.From.TableRefs
if from.Right == nil {
return b.buildSingleTable(sel)
}
return b.buildJoin(sel)
}
func (b *planBuilder) buildSingleTable(sel *ast.SelectStmt) Plan {
from := sel.From.TableRefs
ts, ok := from.Left.(*ast.TableSource)
if !ok {
b.err = ErrUnsupportedType.Gen("Unsupported type %T", from.Left)
return nil
}
var bestPlan Plan
switch v := ts.Source.(type) {
case *ast.TableName:
case *ast.SelectStmt:
bestPlan = b.buildSelect(v)
}
if bestPlan != nil {
return bestPlan
}
tn, ok := ts.Source.(*ast.TableName)
if !ok {
b.err = ErrUnsupportedType.Gen("Unsupported type %T", ts.Source)
return nil
}
conditions := splitWhere(sel.Where)
path := &joinPath{table: tn, conditions: conditions}
candidates := b.buildAllAccessMethodsPlan(path)
var lowestCost float64
for _, v := range candidates {
cost := EstimateCost(b.buildPseudoSelectPlan(v, sel))
if bestPlan == nil {
bestPlan = v
lowestCost = cost
}
if cost < lowestCost {
bestPlan = v
lowestCost = cost
}
}
return bestPlan
}
func (b *planBuilder) buildAllAccessMethodsPlan(path *joinPath) []Plan {
var candidates []Plan
p := b.buildTableScanPlan(path)
candidates = append(candidates, p)
for _, index := range path.table.TableInfo.Indices {
ip := b.buildIndexScanPlan(index, path)
candidates = append(candidates, ip)
}
return candidates
}
func (b *planBuilder) buildTableScanPlan(path *joinPath) Plan {
tn := path.table
p := &TableScan{
Table: tn.TableInfo,
}
// Equal condition contains a column from previous joined table.
p.RefAccess = len(path.eqConds) > 0
p.SetFields(tn.GetResultFields())
var pkName model.CIStr
if p.Table.PKIsHandle {
for _, colInfo := range p.Table.Columns {
if mysql.HasPriKeyFlag(colInfo.Flag) {
pkName = colInfo.Name
}
}
}
for _, con := range path.conditions {
if pkName.L != "" {
checker := conditionChecker{tableName: tn.TableInfo.Name, pkName: pkName}
if checker.check(con) {
p.AccessConditions = append(p.AccessConditions, con)
} else {
p.FilterConditions = append(p.FilterConditions, con)
}
} else {
p.FilterConditions = append(p.FilterConditions, con)
}
}
return p
}
func (b *planBuilder) buildIndexScanPlan(index *model.IndexInfo, path *joinPath) Plan {
tn := path.table
ip := &IndexScan{Table: tn.TableInfo, Index: index}
ip.RefAccess = len(path.eqConds) > 0
ip.SetFields(tn.GetResultFields())
condMap := map[ast.ExprNode]bool{}
for _, con := range path.conditions {
condMap[con] = true
}
out:
// Build equal access conditions first.
// Starts from the first index column, if equal condition is found, add it to access conditions,
// proceed to the next index column. until we can't find any equal condition for the column.
for ip.AccessEqualCount < len(index.Columns) {
for con := range condMap {
binop, ok := con.(*ast.BinaryOperationExpr)
if !ok || binop.Op != opcode.EQ {
continue
}
if ast.IsPreEvaluable(binop.L) {
binop.L, binop.R = binop.R, binop.L
}
if !ast.IsPreEvaluable(binop.R) {
continue
}
cn, ok2 := binop.L.(*ast.ColumnNameExpr)
if !ok2 || cn.Refer.Column.Name.L != index.Columns[ip.AccessEqualCount].Name.L {
continue
}
ip.AccessConditions = append(ip.AccessConditions, con)
delete(condMap, con)
ip.AccessEqualCount++
continue out
}
break
}
for con := range condMap {
if ip.AccessEqualCount < len(ip.Index.Columns) {
// Try to add non-equal access condition for index column at AccessEqualCount.
checker := conditionChecker{tableName: tn.TableInfo.Name, idx: index, columnOffset: ip.AccessEqualCount}
if checker.check(con) {
ip.AccessConditions = append(ip.AccessConditions, con)
} else {
ip.FilterConditions = append(ip.FilterConditions, con)
}
} else {
ip.FilterConditions = append(ip.FilterConditions, con)
}
}
return ip
}
// buildPseudoSelectPlan pre-builds more complete plans that may affect total cost.
func (b *planBuilder) buildPseudoSelectPlan(p Plan, sel *ast.SelectStmt) Plan {
if sel.OrderBy == nil {
return p
}
if sel.GroupBy != nil {
return p
}
if !matchOrder(p, sel.OrderBy.Items) {
np := &Sort{ByItems: sel.OrderBy.Items}
np.SetSrc(p)
p = np
}
if sel.Limit != nil {
np := &Limit{Offset: sel.Limit.Offset, Count: sel.Limit.Count}
np.SetSrc(p)
np.SetLimit(0)
p = np
}
return p
}
func (b *planBuilder) buildSelectLock(src Plan, lock ast.SelectLockType) *SelectLock {
selectLock := &SelectLock{
Lock: lock,
}
selectLock.SetSrc(src)
selectLock.SetFields(src.Fields())
return selectLock
}
func (b *planBuilder) buildSelectFields(src Plan, fields []*ast.ResultField) Plan {
selectFields := &SelectFields{}
selectFields.SetSrc(src)
selectFields.SetFields(fields)
return selectFields
}
func (b *planBuilder) buildAggregate(src Plan, aggFuncs []*ast.AggregateFuncExpr, groupby *ast.GroupByClause) Plan {
// Add aggregate plan.
aggPlan := &Aggregate{
AggFuncs: aggFuncs,
}
aggPlan.SetSrc(src)
if src != nil {
aggPlan.SetFields(src.Fields())
}
if groupby != nil {
aggPlan.GroupByItems = groupby.Items
}
return aggPlan
}
func (b *planBuilder) buildHaving(src Plan, having *ast.HavingClause) Plan {
p := &Having{
Conditions: splitWhere(having.Expr),
}
p.SetSrc(src)
p.SetFields(src.Fields())
return p
}
func (b *planBuilder) buildSort(src Plan, byItems []*ast.ByItem) Plan {
sort := &Sort{
ByItems: byItems,
}
sort.SetSrc(src)
sort.SetFields(src.Fields())
return sort
}
func (b *planBuilder) buildLimit(src Plan, limit *ast.Limit) Plan {
li := &Limit{
Offset: limit.Offset,
Count: limit.Count,
}
li.SetSrc(src)
li.SetFields(src.Fields())
return li
}
func (b *planBuilder) buildPrepare(x *ast.PrepareStmt) Plan {
p := &Prepare{
Name: x.Name,
}
if x.SQLVar != nil {
p.SQLText, _ = x.SQLVar.GetValue().(string)
} else {
p.SQLText = x.SQLText
}
return p
}
func (b *planBuilder) buildAdmin(as *ast.AdminStmt) Plan {
var p Plan
switch as.Tp {
case ast.AdminCheckTable:
p = &CheckTable{Tables: as.Tables}
case ast.AdminShowDDL:
p = &ShowDDL{}
p.SetFields(buildShowDDLFields())
default:
b.err = ErrUnsupportedType.Gen("Unsupported type %T", as)
}
return p
}
func buildShowDDLFields() []*ast.ResultField {
rfs := make([]*ast.ResultField, 0, 6)
rfs = append(rfs, buildResultField("", "SCHEMA_VER", mysql.TypeLonglong, 4))
rfs = append(rfs, buildResultField("", "OWNER", mysql.TypeVarchar, 64))
rfs = append(rfs, buildResultField("", "JOB", mysql.TypeVarchar, 128))
rfs = append(rfs, buildResultField("", "BG_SCHEMA_VER", mysql.TypeLonglong, 4))
rfs = append(rfs, buildResultField("", "BG_OWNER", mysql.TypeVarchar, 64))
rfs = append(rfs, buildResultField("", "BG_JOB", mysql.TypeVarchar, 128))
return rfs
}
func buildResultField(tableName, name string, tp byte, size int) *ast.ResultField {
cs := charset.CharsetBin
cl := charset.CharsetBin
flag := mysql.UnsignedFlag
if tp == mysql.TypeVarchar || tp == mysql.TypeBlob {
cs = mysql.DefaultCharset
cl = mysql.DefaultCollationName
flag = 0
}
fieldType := types.FieldType{
Charset: cs,
Collate: cl,
Tp: tp,
Flen: size,
Flag: uint(flag),
}
colInfo := &model.ColumnInfo{
Name: model.NewCIStr(name),
FieldType: fieldType,
}
expr := &ast.ValueExpr{}
expr.SetType(&fieldType)
return &ast.ResultField{
Column: colInfo,
ColumnAsName: colInfo.Name,
TableAsName: model.NewCIStr(tableName),
DBName: model.NewCIStr(infoschema.Name),
Expr: expr,
}
}
// matchOrder checks if the plan has the same ordering as items.
func matchOrder(p Plan, items []*ast.ByItem) bool {
switch x := p.(type) {
case *Aggregate:
return false
case *IndexScan:
if len(items) > len(x.Index.Columns) {
return false
}
for i, item := range items {
if item.Desc {
return false
}
var rf *ast.ResultField
switch y := item.Expr.(type) {
case *ast.ColumnNameExpr:
rf = y.Refer
case *ast.PositionExpr:
rf = y.Refer
default:
return false
}
if rf.Table.Name.L != x.Table.Name.L || rf.Column.Name.L != x.Index.Columns[i].Name.L {
return false
}
}
return true
case *TableScan:
if len(items) != 1 || !x.Table.PKIsHandle {
return false
}
if items[0].Desc {
return false
}
var refer *ast.ResultField
switch x := items[0].Expr.(type) {
case *ast.ColumnNameExpr:
refer = x.Refer
case *ast.PositionExpr:
refer = x.Refer
default:
return false
}
if mysql.HasPriKeyFlag(refer.Column.Flag) {
return true
}
return false
case *JoinOuter:
return false
case *JoinInner:
return false
case *Sort:
// Sort plan should not be checked here as there should only be one sort plan in a plan tree.
return false
case WithSrcPlan:
return matchOrder(x.Src(), items)
}
return true
}
// splitWhere split a where expression to a list of AND conditions.
func splitWhere(where ast.ExprNode) []ast.ExprNode {
var conditions []ast.ExprNode
switch x := where.(type) {
case nil:
case *ast.BinaryOperationExpr:
if x.Op == opcode.AndAnd {
conditions = append(conditions, splitWhere(x.L)...)
conditions = append(conditions, splitWhere(x.R)...)
} else {
conditions = append(conditions, x)
}
case *ast.ParenthesesExpr:
conditions = append(conditions, splitWhere(x.Expr)...)
default:
conditions = append(conditions, where)
}
return conditions
}
// SubQueryBuilder is the interface for building SubQuery executor.
type SubQueryBuilder interface {
Build(p Plan) ast.SubqueryExec
}
// subqueryVisitor visits AST and handles SubqueryExpr.
type subqueryVisitor struct {
builder *planBuilder
}
func (se *subqueryVisitor) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
switch x := in.(type) {
case *ast.SubqueryExpr:
p := se.builder.build(x.Query)
// The expr pointor is copyed into ResultField when running name resolver.
// So we can not just replace the expr node in AST. We need to put SubQuery into the expr.
// See: optimizer.nameResolver.createResultFields()
x.SubqueryExec = se.builder.sb.Build(p)
return in, true
case *ast.Join:
// SubSelect in from clause will be handled in buildJoin().
return in, true
}
return in, false
}
func (se *subqueryVisitor) Leave(in ast.Node) (out ast.Node, ok bool) {
return in, true
}
func (b *planBuilder) buildUnion(union *ast.UnionStmt) Plan {
sels := make([]Plan, len(union.SelectList.Selects))
for i, sel := range union.SelectList.Selects {
sels[i] = b.buildSelect(sel)
}
var p Plan
p = &Union{
Selects: sels,
}
unionFields := union.GetResultFields()
for _, sel := range sels {
for i, f := range sel.Fields() {
if i == len(unionFields) {
b.err = errors.New("The used SELECT statements have a different number of columns")
return nil
}
uField := unionFields[i]
/*
* The lengths of the columns in the UNION result take into account the values retrieved by all of the SELECT statements
* SELECT REPEAT('a',1) UNION SELECT REPEAT('b',10);
* +---------------+
* | REPEAT('a',1) |
* +---------------+
* | a |
* | bbbbbbbbbb |
* +---------------+
*/
if f.Column.Flen > uField.Column.Flen {
uField.Column.Flen = f.Column.Flen
}
// For select nul union select "abc", we should not convert "abc" to nil.
// And the result field type should be VARCHAR.
if uField.Column.Tp == 0 || uField.Column.Tp == mysql.TypeNull {
uField.Column.Tp = f.Column.Tp
}
}
}
for _, v := range unionFields {
v.Expr.SetType(&v.Column.FieldType)
}
p.SetFields(unionFields)
if union.Distinct {
p = b.buildDistinct(p)
}
if union.OrderBy != nil {
p = b.buildSort(p, union.OrderBy.Items)
}
if union.Limit != nil {
p = b.buildLimit(p, union.Limit)
}
return p
}
func (b *planBuilder) buildDistinct(src Plan) Plan {
d := &Distinct{}
d.src = src
d.SetFields(src.Fields())
return d
}
func (b *planBuilder) buildUpdate(update *ast.UpdateStmt) Plan {
sel := &ast.SelectStmt{From: update.TableRefs, Where: update.Where, OrderBy: update.Order, Limit: update.Limit}
p := b.buildFrom(sel)
if sel.OrderBy != nil && !matchOrder(p, sel.OrderBy.Items) {
p = b.buildSort(p, sel.OrderBy.Items)
if b.err != nil {
return nil
}
}
if sel.Limit != nil {
p = b.buildLimit(p, sel.Limit)
if b.err != nil {
return nil
}
}
orderedList := b.buildUpdateLists(update.List, p.Fields())
if b.err != nil {
return nil
}
return &Update{OrderedList: orderedList, SelectPlan: p}
}
func (b *planBuilder) buildUpdateLists(list []*ast.Assignment, fields []*ast.ResultField) []*ast.Assignment {
newList := make([]*ast.Assignment, len(fields))
for _, assign := range list {
offset, err := columnOffsetInFields(assign.Column, fields)
if err != nil {
b.err = errors.Trace(err)
return nil
}
newList[offset] = assign
}
return newList
}
func (b *planBuilder) buildDelete(del *ast.DeleteStmt) Plan {
sel := &ast.SelectStmt{From: del.TableRefs, Where: del.Where, OrderBy: del.Order, Limit: del.Limit}
p := b.buildFrom(sel)
if sel.OrderBy != nil && !matchOrder(p, sel.OrderBy.Items) {
p = b.buildSort(p, sel.OrderBy.Items)
if b.err != nil {
return nil
}
}
if sel.Limit != nil {
p = b.buildLimit(p, sel.Limit)
if b.err != nil {
return nil
}
}
var tables []*ast.TableName
if del.Tables != nil {
tables = del.Tables.Tables
}
return &Delete{
Tables: tables,
IsMultiTable: del.IsMultiTable,
SelectPlan: p,
}
}
func columnOffsetInFields(cn *ast.ColumnName, fields []*ast.ResultField) (int, error) {
offset := -1
tableNameL := cn.Table.L
columnNameL := cn.Name.L
if tableNameL != "" {
for i, f := range fields {
// Check table name.
if f.TableAsName.L != "" {
if tableNameL != f.TableAsName.L {
continue
}
} else {
if tableNameL != f.Table.Name.L {
continue
}
}
// Check column name.
if f.ColumnAsName.L != "" {
if columnNameL != f.ColumnAsName.L {
continue
}
} else {
if columnNameL != f.Column.Name.L {
continue
}
}
offset = i
}
} else {
for i, f := range fields {
matchAsName := f.ColumnAsName.L != "" && f.ColumnAsName.L == columnNameL
matchColumnName := f.ColumnAsName.L == "" && f.Column.Name.L == columnNameL
if matchAsName || matchColumnName {
if offset != -1 {
return -1, errors.Errorf("column %s is ambiguous.", cn.Name.O)
}
offset = i
}
}
}
if offset == -1 {
return -1, errors.Errorf("column %s not found", cn.Name.O)
}
return offset, nil
}
func (b *planBuilder) buildShow(show *ast.ShowStmt) Plan {
var p Plan
p = &Show{
Tp: show.Tp,
DBName: show.DBName,
Table: show.Table,
Column: show.Column,
Flag: show.Flag,
Full: show.Full,
User: show.User,
}
p.SetFields(show.GetResultFields())
var conditions []ast.ExprNode
if show.Pattern != nil {
conditions = append(conditions, show.Pattern)
}
if show.Where != nil {
conditions = append(conditions, show.Where)
}
if len(conditions) != 0 {
filter := &Filter{Conditions: conditions}
filter.SetSrc(p)
p = filter
}
return p
}
func (b *planBuilder) buildSimple(node ast.StmtNode) Plan {
return &Simple{Statement: node}
}
func (b *planBuilder) buildInsert(insert *ast.InsertStmt) Plan {
insertPlan := &Insert{
Table: insert.Table,
Columns: insert.Columns,
Lists: insert.Lists,
Setlist: insert.Setlist,
OnDuplicate: insert.OnDuplicate,
IsReplace: insert.IsReplace,
Priority: insert.Priority,
}
if insert.Select != nil {
insertPlan.SelectPlan = b.build(insert.Select)
if b.err != nil {
return nil
}
}
return insertPlan
}
func (b *planBuilder) buildDDL(node ast.DDLNode) Plan {
return &DDL{Statement: node}
}
func (b *planBuilder) buildExplain(explain *ast.ExplainStmt) Plan {
if show, ok := explain.Stmt.(*ast.ShowStmt); ok {
return b.buildShow(show)
}
targetPlan := b.build(explain.Stmt)
if b.err != nil {
return nil
}
p := &Explain{StmtPlan: targetPlan}
p.SetFields(buildExplainFields())
return p
}
// See: https://dev.mysql.com/doc/refman/5.7/en/explain-output.html
func buildExplainFields() []*ast.ResultField {
rfs := make([]*ast.ResultField, 0, 10)
rfs = append(rfs, buildResultField("", "id", mysql.TypeLonglong, 4))
rfs = append(rfs, buildResultField("", "select_type", mysql.TypeVarchar, 128))
rfs = append(rfs, buildResultField("", "table", mysql.TypeVarchar, 128))
rfs = append(rfs, buildResultField("", "type", mysql.TypeVarchar, 128))
rfs = append(rfs, buildResultField("", "possible_keys", mysql.TypeVarchar, 128))
rfs = append(rfs, buildResultField("", "key", mysql.TypeVarchar, 128))
rfs = append(rfs, buildResultField("", "key_len", mysql.TypeVarchar, 128))
rfs = append(rfs, buildResultField("", "ref", mysql.TypeVarchar, 128))
rfs = append(rfs, buildResultField("", "rows", mysql.TypeVarchar, 128))
rfs = append(rfs, buildResultField("", "Extra", mysql.TypeVarchar, 128))
return rfs
}