Files
tidb/plan/planbuilder.go

504 lines
15 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/juju/errors"
"github.com/pingcap/tidb/ast"
"github.com/pingcap/tidb/context"
"github.com/pingcap/tidb/expression"
"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")
SystemInternalErrorType = terror.ClassOptimizerPlan.New(SystemInternalError, "System internal error")
)
// Error codes.
const (
CodeUnsupportedType terror.ErrCode = 1
SystemInternalError terror.ErrCode = 2
)
// planBuilder builds Plan from an ast.Node.
// It just builds the ast node straightforwardly.
type planBuilder struct {
err error
hasAgg bool
obj interface{}
allocator *idAllocator
ctx context.Context
is infoschema.InfoSchema
outerSchemas []expression.Schema
// colMapper stores the column that must be pre-resolved.
colMapper map[*ast.ColumnNameExpr]int
}
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.LoadDataStmt:
return b.buildLoadData(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.ShowStmt:
return b.buildShow(x)
case *ast.AnalyzeTableStmt, *ast.BinlogStmt, *ast.FlushTableStmt, *ast.UseStmt, *ast.SetStmt, *ast.DoStmt, *ast.BeginStmt,
*ast.CommitStmt, *ast.RollbackStmt, *ast.CreateUserStmt, *ast.SetPwdStmt, *ast.GrantStmt, *ast.DropUserStmt:
return b.buildSimple(node.(ast.StmtNode))
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},
}
agg.SetType(ve.GetType())
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 availableIndices(table *ast.TableName) (indices []*model.IndexInfo, includeTableScan bool) {
var usableHints []*ast.IndexHint
for _, hint := range table.IndexHints {
if hint.HintScope == ast.HintForScan {
usableHints = append(usableHints, hint)
}
}
publicIndices := make([]*model.IndexInfo, 0, len(table.TableInfo.Indices))
for _, index := range table.TableInfo.Indices {
if index.State == model.StatePublic {
publicIndices = append(publicIndices, index)
}
}
if len(usableHints) == 0 {
return publicIndices, true
}
var hasUse bool
var ignores []*model.IndexInfo
for _, hint := range usableHints {
switch hint.HintType {
case ast.HintUse, ast.HintForce:
// Currently we don't distinguish between Force and Use because our cost estimation is not reliable.
hasUse = true
for _, idxName := range hint.IndexNames {
idx := findIndexByName(publicIndices, idxName)
if idx != nil {
indices = append(indices, idx)
}
}
case ast.HintIgnore:
// Collect all the ignore index hints.
for _, idxName := range hint.IndexNames {
idx := findIndexByName(publicIndices, idxName)
if idx != nil {
ignores = append(ignores, idx)
}
}
}
}
indices = removeIgnores(indices, ignores)
// If we have got FORCE or USE index hint, table scan is excluded.
if len(indices) != 0 {
return indices, false
}
if hasUse {
// Empty use hint means don't use any index.
return nil, true
}
return removeIgnores(publicIndices, ignores), true
}
func removeIgnores(indices, ignores []*model.IndexInfo) []*model.IndexInfo {
if len(ignores) == 0 {
return indices
}
var remainedIndices []*model.IndexInfo
for _, index := range indices {
if findIndexByName(ignores, index.Name) == nil {
remainedIndices = append(remainedIndices, index)
}
}
return remainedIndices
}
func findIndexByName(indices []*model.IndexInfo, name model.CIStr) *model.IndexInfo {
for _, idx := range indices {
if idx.Name.L == name.L {
return idx
}
}
return nil
}
func (b *planBuilder) buildSelectLock(src Plan, lock ast.SelectLockType) *SelectLock {
selectLock := &SelectLock{
Lock: lock,
baseLogicalPlan: newBaseLogicalPlan(Lock, b.allocator),
}
selectLock.self = selectLock
selectLock.initID()
addChild(selectLock, src)
selectLock.SetSchema(src.GetSchema())
return selectLock
}
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.SetSchema(buildShowDDLFields())
default:
b.err = ErrUnsupportedType.Gen("Unsupported type %T", as)
}
return p
}
func buildShowDDLFields() expression.Schema {
schema := make(expression.Schema, 0, 6)
schema = append(schema, buildColumn("", "SCHEMA_VER", mysql.TypeLonglong, 4))
schema = append(schema, buildColumn("", "OWNER", mysql.TypeVarchar, 64))
schema = append(schema, buildColumn("", "JOB", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn("", "BG_SCHEMA_VER", mysql.TypeLonglong, 4))
schema = append(schema, buildColumn("", "BG_OWNER", mysql.TypeVarchar, 64))
schema = append(schema, buildColumn("", "BG_JOB", mysql.TypeVarchar, 128))
return schema
}
func buildColumn(tableName, name string, tp byte, size int) *expression.Column {
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),
}
return &expression.Column{
ColName: model.NewCIStr(name),
TblName: model.NewCIStr(tableName),
DBName: model.NewCIStr(infoschema.Name),
RetType: fieldType,
}
}
// 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
}
func (b *planBuilder) buildShow(show *ast.ShowStmt) Plan {
var resultPlan Plan
p := &Show{
Tp: show.Tp,
DBName: show.DBName,
Table: show.Table,
Column: show.Column,
Flag: show.Flag,
Full: show.Full,
User: show.User,
baseLogicalPlan: newBaseLogicalPlan("Show", b.allocator),
}
resultPlan = p
p.initID()
p.self = p
switch show.Tp {
case ast.ShowProcedureStatus:
p.SetSchema(buildShowProcedureSchema())
case ast.ShowTriggers:
p.SetSchema(buildShowTriggerSchema())
default:
p.SetSchema(expression.ResultFieldsToSchema(show.GetResultFields()))
}
for i, col := range p.schema {
col.Position = i
}
var conditions []expression.Expression
if show.Pattern != nil {
expr, _, err := b.rewrite(show.Pattern, p, nil, false)
if err != nil {
b.err = errors.Trace(err)
return nil
}
conditions = append(conditions, expr)
}
if show.Where != nil {
conds := splitWhere(show.Where)
for _, cond := range conds {
expr, _, err := b.rewrite(cond, p, nil, false)
if err != nil {
b.err = errors.Trace(err)
return nil
}
conditions = append(conditions, expr)
}
}
if len(conditions) != 0 {
sel := &Selection{
baseLogicalPlan: newBaseLogicalPlan(Sel, b.allocator),
Conditions: conditions,
}
sel.initID()
sel.self = sel
addChild(sel, p)
resultPlan = sel
}
return resultPlan
}
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,
Ignore: insert.Ignore,
baseLogicalPlan: newBaseLogicalPlan(Ins, b.allocator),
}
insertPlan.initID()
insertPlan.self = insertPlan
if insert.Select != nil {
selectPlan := b.build(insert.Select)
if b.err != nil {
return nil
}
addChild(insertPlan, selectPlan)
}
return insertPlan
}
func (b *planBuilder) buildLoadData(ld *ast.LoadDataStmt) Plan {
p := &LoadData{
IsLocal: ld.IsLocal,
Path: ld.Path,
Table: ld.Table,
FieldsInfo: ld.FieldsInfo,
LinesInfo: ld.LinesInfo,
}
return p
}
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, err := Optimize(b.ctx, explain.Stmt, b.is)
if err != nil {
b.err = errors.Trace(err)
return nil
}
p := &Explain{StmtPlan: targetPlan}
addChild(p, targetPlan)
col := &expression.Column{
RetType: types.NewFieldType(mysql.TypeString),
}
p.SetSchema([]*expression.Column{col, col})
return p
}
func buildShowProcedureSchema() expression.Schema {
tblName := "ROUTINES"
schema := make(expression.Schema, 0, 11)
schema = append(schema, buildColumn(tblName, "Db", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn(tblName, "Name", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn(tblName, "Type", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn(tblName, "Definer", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn(tblName, "Modified", mysql.TypeDatetime, 19))
schema = append(schema, buildColumn(tblName, "Created", mysql.TypeDatetime, 19))
schema = append(schema, buildColumn(tblName, "Security_type", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn(tblName, "Comment", mysql.TypeBlob, 196605))
schema = append(schema, buildColumn(tblName, "character_set_client", mysql.TypeVarchar, 32))
schema = append(schema, buildColumn(tblName, "collation_connection", mysql.TypeVarchar, 32))
schema = append(schema, buildColumn(tblName, "Database Collation", mysql.TypeVarchar, 32))
return schema
}
func buildShowTriggerSchema() expression.Schema {
tblName := "TRIGGERS"
schema := make(expression.Schema, 0, 11)
schema = append(schema, buildColumn(tblName, "Trigger", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn(tblName, "Event", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn(tblName, "Table", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn(tblName, "Statement", mysql.TypeBlob, 196605))
schema = append(schema, buildColumn(tblName, "Timing", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn(tblName, "Created", mysql.TypeDatetime, 19))
schema = append(schema, buildColumn(tblName, "sql_mode", mysql.TypeBlob, 8192))
schema = append(schema, buildColumn(tblName, "Definer", mysql.TypeVarchar, 128))
schema = append(schema, buildColumn(tblName, "character_set_client", mysql.TypeVarchar, 32))
schema = append(schema, buildColumn(tblName, "collation_connection", mysql.TypeVarchar, 32))
schema = append(schema, buildColumn(tblName, "Database Collation", mysql.TypeVarchar, 32))
return schema
}