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preprocess.go
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preprocess.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 (
"math"
"strings"
"github.com/juju/errors"
"github.com/pingcap/tidb/ast"
"github.com/pingcap/tidb/ddl"
"github.com/pingcap/tidb/infoschema"
"github.com/pingcap/tidb/model"
"github.com/pingcap/tidb/mysql"
"github.com/pingcap/tidb/parser"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/charset"
)
// Preprocess resolves table names of the node, and checks some statements validation.
func Preprocess(ctx sessionctx.Context, node ast.Node, is infoschema.InfoSchema, inPrepare bool) error {
v := preprocessor{is: is, ctx: ctx, inPrepare: inPrepare}
node.Accept(&v)
return errors.Trace(v.err)
}
// preprocessor is an ast.Visitor that preprocess
// ast Nodes parsed from parser.
type preprocessor struct {
is infoschema.InfoSchema
ctx sessionctx.Context
err error
inPrepare bool
// inCreateOrDropTable is true when visiting create/drop table statement.
inCreateOrDropTable bool
}
func (p *preprocessor) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
switch node := in.(type) {
case *ast.CreateTableStmt:
p.inCreateOrDropTable = true
p.checkCreateTableGrammar(node)
case *ast.DropTableStmt:
p.inCreateOrDropTable = true
p.checkDropTableGrammar(node)
case *ast.RenameTableStmt:
p.inCreateOrDropTable = true
case *ast.CreateIndexStmt:
p.checkCreateIndexGrammar(node)
case *ast.AlterTableStmt:
p.resolveAlterTableStmt(node)
p.checkAlterTableGrammar(node)
case *ast.CreateDatabaseStmt:
p.checkCreateDatabaseGrammar(node)
case *ast.DropDatabaseStmt:
p.checkDropDatabaseGrammar(node)
case *ast.ShowStmt:
p.resolveShowStmt(node)
case *ast.DeleteTableList:
return in, true
}
return in, p.err != nil
}
func (p *preprocessor) Leave(in ast.Node) (out ast.Node, ok bool) {
switch x := in.(type) {
case *ast.CreateTableStmt:
p.inCreateOrDropTable = false
p.checkAutoIncrement(x)
case *ast.DropTableStmt, *ast.AlterTableStmt, *ast.RenameTableStmt:
p.inCreateOrDropTable = false
case *ast.ParamMarkerExpr:
if !p.inPrepare {
p.err = parser.ErrSyntax.Gen("syntax error, unexpected '?'")
return
}
case *ast.ExplainStmt:
if _, ok := x.Stmt.(*ast.ShowStmt); ok {
break
}
valid := false
for i, length := 0, len(ast.ExplainFormats); i < length; i++ {
if strings.ToLower(x.Format) == ast.ExplainFormats[i] {
valid = true
break
}
}
if !valid {
p.err = ErrUnknownExplainFormat.GenByArgs(x.Format)
}
case *ast.TableName:
p.handleTableName(x)
}
return in, p.err == nil
}
func checkAutoIncrementOp(colDef *ast.ColumnDef, num int) (bool, error) {
var hasAutoIncrement bool
if colDef.Options[num].Tp == ast.ColumnOptionAutoIncrement {
hasAutoIncrement = true
if len(colDef.Options) == num+1 {
return hasAutoIncrement, nil
}
for _, op := range colDef.Options[num+1:] {
if op.Tp == ast.ColumnOptionDefaultValue && !op.Expr.GetDatum().IsNull() {
return hasAutoIncrement, errors.Errorf("Invalid default value for '%s'", colDef.Name.Name.O)
}
}
}
if colDef.Options[num].Tp == ast.ColumnOptionDefaultValue && len(colDef.Options) != num+1 {
if colDef.Options[num].Expr.GetDatum().IsNull() {
return hasAutoIncrement, nil
}
for _, op := range colDef.Options[num+1:] {
if op.Tp == ast.ColumnOptionAutoIncrement {
return hasAutoIncrement, errors.Errorf("Invalid default value for '%s'", colDef.Name.Name.O)
}
}
}
return hasAutoIncrement, nil
}
func isConstraintKeyTp(constraints []*ast.Constraint, colDef *ast.ColumnDef) bool {
for _, c := range constraints {
// If the constraint as follows: primary key(c1, c2)
// we only support c1 column can be auto_increment.
if colDef.Name.Name.L != c.Keys[0].Column.Name.L {
continue
}
switch c.Tp {
case ast.ConstraintPrimaryKey, ast.ConstraintKey, ast.ConstraintIndex,
ast.ConstraintUniq, ast.ConstraintUniqIndex, ast.ConstraintUniqKey:
return true
}
}
return false
}
func (p *preprocessor) checkAutoIncrement(stmt *ast.CreateTableStmt) {
var (
isKey bool
count int
autoIncrementCol *ast.ColumnDef
)
for _, colDef := range stmt.Cols {
var hasAutoIncrement bool
for i, op := range colDef.Options {
ok, err := checkAutoIncrementOp(colDef, i)
if err != nil {
p.err = err
return
}
if ok {
hasAutoIncrement = true
}
switch op.Tp {
case ast.ColumnOptionPrimaryKey, ast.ColumnOptionUniqKey:
isKey = true
}
}
if hasAutoIncrement {
count++
autoIncrementCol = colDef
}
}
if count < 1 {
return
}
if !isKey {
isKey = isConstraintKeyTp(stmt.Constraints, autoIncrementCol)
}
autoIncrementMustBeKey := true
for _, opt := range stmt.Options {
if opt.Tp == ast.TableOptionEngine && strings.EqualFold(opt.StrValue, "MyISAM") {
autoIncrementMustBeKey = false
}
}
if (autoIncrementMustBeKey && !isKey) || count > 1 {
p.err = errors.New("Incorrect table definition; there can be only one auto column and it must be defined as a key")
}
switch autoIncrementCol.Tp.Tp {
case mysql.TypeTiny, mysql.TypeShort, mysql.TypeLong,
mysql.TypeFloat, mysql.TypeDouble, mysql.TypeLonglong, mysql.TypeInt24:
default:
p.err = errors.Errorf("Incorrect column specifier for column '%s'", autoIncrementCol.Name.Name.O)
}
}
func (p *preprocessor) checkCreateDatabaseGrammar(stmt *ast.CreateDatabaseStmt) {
if isIncorrectName(stmt.Name) {
p.err = ddl.ErrWrongDBName.GenByArgs(stmt.Name)
}
}
func (p *preprocessor) checkDropDatabaseGrammar(stmt *ast.DropDatabaseStmt) {
if isIncorrectName(stmt.Name) {
p.err = ddl.ErrWrongDBName.GenByArgs(stmt.Name)
}
}
func (p *preprocessor) checkCreateTableGrammar(stmt *ast.CreateTableStmt) {
tName := stmt.Table.Name.String()
if isIncorrectName(tName) {
p.err = ddl.ErrWrongTableName.GenByArgs(tName)
return
}
countPrimaryKey := 0
for _, colDef := range stmt.Cols {
if err := checkColumn(colDef); err != nil {
p.err = errors.Trace(err)
return
}
countPrimaryKey += isPrimary(colDef.Options)
if countPrimaryKey > 1 {
p.err = infoschema.ErrMultiplePriKey
return
}
}
for _, constraint := range stmt.Constraints {
switch tp := constraint.Tp; tp {
case ast.ConstraintKey, ast.ConstraintIndex, ast.ConstraintUniq, ast.ConstraintUniqKey, ast.ConstraintUniqIndex:
err := checkIndexInfo(constraint.Name, constraint.Keys)
if err != nil {
p.err = err
return
}
case ast.ConstraintPrimaryKey:
if countPrimaryKey > 0 {
p.err = infoschema.ErrMultiplePriKey
return
}
countPrimaryKey++
err := checkIndexInfo(constraint.Name, constraint.Keys)
if err != nil {
p.err = err
return
}
}
}
}
func (p *preprocessor) checkDropTableGrammar(stmt *ast.DropTableStmt) {
for _, t := range stmt.Tables {
if isIncorrectName(t.Name.String()) {
p.err = ddl.ErrWrongTableName.GenByArgs(t.Name.String())
return
}
}
}
func isPrimary(ops []*ast.ColumnOption) int {
for _, op := range ops {
if op.Tp == ast.ColumnOptionPrimaryKey {
return 1
}
}
return 0
}
func (p *preprocessor) checkCreateIndexGrammar(stmt *ast.CreateIndexStmt) {
tName := stmt.Table.Name.String()
if isIncorrectName(tName) {
p.err = ddl.ErrWrongTableName.GenByArgs(tName)
return
}
p.err = checkIndexInfo(stmt.IndexName, stmt.IndexColNames)
}
func (p *preprocessor) checkAlterTableGrammar(stmt *ast.AlterTableStmt) {
tName := stmt.Table.Name.String()
if isIncorrectName(tName) {
p.err = ddl.ErrWrongTableName.GenByArgs(tName)
return
}
specs := stmt.Specs
for _, spec := range specs {
if spec.NewTable != nil {
ntName := spec.NewTable.Name.String()
if isIncorrectName(ntName) {
p.err = ddl.ErrWrongTableName.GenByArgs(ntName)
return
}
}
for _, colDef := range spec.NewColumns {
if p.err = checkColumn(colDef); p.err != nil {
return
}
}
switch spec.Tp {
case ast.AlterTableAddConstraint:
switch spec.Constraint.Tp {
case ast.ConstraintKey, ast.ConstraintIndex, ast.ConstraintUniq, ast.ConstraintUniqIndex,
ast.ConstraintUniqKey:
p.err = checkIndexInfo(spec.Constraint.Name, spec.Constraint.Keys)
if p.err != nil {
return
}
default:
// Nothing to do now.
}
default:
// Nothing to do now.
}
}
}
// checkDuplicateColumnName checks if index exists duplicated columns.
func checkDuplicateColumnName(indexColNames []*ast.IndexColName) error {
colNames := make(map[string]struct{}, len(indexColNames))
for _, indexColName := range indexColNames {
name := indexColName.Column.Name
if _, ok := colNames[name.L]; ok {
return infoschema.ErrColumnExists.GenByArgs(name)
}
colNames[name.L] = struct{}{}
}
return nil
}
// checkIndexInfo checks index name and index column names.
func checkIndexInfo(indexName string, indexColNames []*ast.IndexColName) error {
if strings.EqualFold(indexName, mysql.PrimaryKeyName) {
return ddl.ErrWrongNameForIndex.GenByArgs(indexName)
}
if len(indexColNames) > mysql.MaxKeyParts {
return infoschema.ErrTooManyKeyParts.GenByArgs(mysql.MaxKeyParts)
}
return checkDuplicateColumnName(indexColNames)
}
// checkColumn checks if the column definition is valid.
// See https://dev.mysql.com/doc/refman/5.7/en/storage-requirements.html
func checkColumn(colDef *ast.ColumnDef) error {
// Check column name.
cName := colDef.Name.Name.String()
if isIncorrectName(cName) {
return ddl.ErrWrongColumnName.GenByArgs(cName)
}
if isInvalidDefaultValue(colDef) {
return types.ErrInvalidDefault.GenByArgs(colDef.Name.Name.O)
}
// Check column type.
tp := colDef.Tp
if tp == nil {
return nil
}
if tp.Flen > math.MaxUint32 {
return types.ErrTooBigDisplayWidth.Gen("Display width out of range for column '%s' (max = %d)", colDef.Name.Name.O, math.MaxUint32)
}
switch tp.Tp {
case mysql.TypeString:
if tp.Flen != types.UnspecifiedLength && tp.Flen > mysql.MaxFieldCharLength {
return types.ErrTooBigFieldLength.Gen("Column length too big for column '%s' (max = %d); use BLOB or TEXT instead", colDef.Name.Name.O, mysql.MaxFieldCharLength)
}
case mysql.TypeVarchar:
maxFlen := mysql.MaxFieldVarCharLength
cs := tp.Charset
// TODO: TableDefaultCharset-->DatabaseDefaultCharset-->SystemDefaultCharset.
// TODO: Change TableOption parser to parse collate.
// Reference https://github.com/pingcap/tidb/blob/b091e828cfa1d506b014345fb8337e424a4ab905/ddl/ddl_api.go#L185-L204
if len(tp.Charset) == 0 {
cs = mysql.DefaultCharset
}
desc, err := charset.GetCharsetDesc(cs)
if err != nil {
return errors.Trace(err)
}
maxFlen /= desc.Maxlen
if tp.Flen != types.UnspecifiedLength && tp.Flen > maxFlen {
return types.ErrTooBigFieldLength.Gen("Column length too big for column '%s' (max = %d); use BLOB or TEXT instead", colDef.Name.Name.O, maxFlen)
}
case mysql.TypeFloat, mysql.TypeDouble:
if tp.Decimal > mysql.MaxFloatingTypeScale {
return types.ErrTooBigScale.GenByArgs(tp.Decimal, colDef.Name.Name.O, mysql.MaxFloatingTypeScale)
}
if tp.Flen > mysql.MaxFloatingTypeWidth {
return types.ErrTooBigPrecision.GenByArgs(tp.Flen, colDef.Name.Name.O, mysql.MaxFloatingTypeWidth)
}
case mysql.TypeSet:
if len(tp.Elems) > mysql.MaxTypeSetMembers {
return types.ErrTooBigSet.Gen("Too many strings for column %s and SET", colDef.Name.Name.O)
}
// Check set elements. See https://dev.mysql.com/doc/refman/5.7/en/set.html .
for _, str := range colDef.Tp.Elems {
if strings.Contains(str, ",") {
return types.ErrIllegalValueForType.GenByArgs(types.TypeStr(tp.Tp), str)
}
}
case mysql.TypeNewDecimal:
if tp.Decimal > mysql.MaxDecimalScale {
return types.ErrTooBigScale.GenByArgs(tp.Decimal, colDef.Name.Name.O, mysql.MaxDecimalScale)
}
if tp.Flen > mysql.MaxDecimalWidth {
return types.ErrTooBigPrecision.GenByArgs(tp.Flen, colDef.Name.Name.O, mysql.MaxDecimalWidth)
}
default:
// TODO: Add more types.
}
return nil
}
// isDefaultValNowSymFunc checks whether defaul value is a NOW() builtin function.
func isDefaultValNowSymFunc(expr ast.ExprNode) bool {
if funcCall, ok := expr.(*ast.FuncCallExpr); ok {
// Default value NOW() is transformed to CURRENT_TIMESTAMP() in parser.
if funcCall.FnName.L == ast.CurrentTimestamp {
return true
}
}
return false
}
func isInvalidDefaultValue(colDef *ast.ColumnDef) bool {
tp := colDef.Tp
// Check the last default value.
for i := len(colDef.Options) - 1; i >= 0; i-- {
columnOpt := colDef.Options[i]
if columnOpt.Tp == ast.ColumnOptionDefaultValue {
if !(tp.Tp == mysql.TypeTimestamp || tp.Tp == mysql.TypeDatetime) && isDefaultValNowSymFunc(columnOpt.Expr) {
return true
}
break
}
}
return false
}
// isIncorrectName checks if the identifier is incorrect.
// See https://dev.mysql.com/doc/refman/5.7/en/identifiers.html
func isIncorrectName(name string) bool {
if len(name) == 0 {
return true
}
if name[len(name)-1] == ' ' {
return true
}
return false
}
func (p *preprocessor) handleTableName(tn *ast.TableName) {
if tn.Schema.L == "" {
currentDB := p.ctx.GetSessionVars().CurrentDB
if currentDB == "" {
p.err = errors.Trace(ErrNoDB)
return
}
tn.Schema = model.NewCIStr(currentDB)
}
if p.inCreateOrDropTable {
// The table may not exist in create table or drop table statement.
// Skip resolving the table to avoid error.
return
}
table, err := p.is.TableByName(tn.Schema, tn.Name)
if err != nil {
p.err = errors.Trace(err)
return
}
tn.TableInfo = table.Meta()
dbInfo, _ := p.is.SchemaByName(tn.Schema)
tn.DBInfo = dbInfo
}
func (p *preprocessor) resolveShowStmt(node *ast.ShowStmt) {
if node.DBName == "" {
if node.Table != nil && node.Table.Schema.L != "" {
node.DBName = node.Table.Schema.O
} else {
node.DBName = p.ctx.GetSessionVars().CurrentDB
}
} else if node.Table != nil && node.Table.Schema.L == "" {
node.Table.Schema = model.NewCIStr(node.DBName)
}
if node.User != nil && node.User.CurrentUser {
// Fill the Username and Hostname with the current user.
currentUser := p.ctx.GetSessionVars().User
if currentUser != nil {
node.User.Username = currentUser.Username
node.User.Hostname = currentUser.Hostname
}
}
}
func (p *preprocessor) resolveAlterTableStmt(node *ast.AlterTableStmt) {
for _, spec := range node.Specs {
if spec.Tp == ast.AlterTableRenameTable {
p.inCreateOrDropTable = true
break
}
}
}