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

91 lines
3.2 KiB

// 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 optimizer
import (
"github.com/juju/errors"
"github.com/pingcap/tidb/ast"
"github.com/pingcap/tidb/context"
"github.com/pingcap/tidb/infoschema"
"github.com/pingcap/tidb/mysql"
"github.com/pingcap/tidb/optimizer/plan"
"github.com/pingcap/tidb/terror"
)
// Optimize does optimization and creates a Plan.
// The node must be prepared first.
func Optimize(ctx context.Context, node ast.Node, sb plan.SubQueryBuilder) (plan.Plan, error) {
// We have to infer type again because after parameter is set, the expression type may change.
if err := InferType(node); err != nil {
return nil, errors.Trace(err)
}
if err := logicOptimize(ctx, node); err != nil {
return nil, errors.Trace(err)
}
p, err := plan.BuildPlan(node, sb)
if err != nil {
return nil, errors.Trace(err)
}
err = plan.Refine(p)
if err != nil {
return nil, errors.Trace(err)
}
return p, nil
}
// Prepare prepares a raw statement parsed from parser.
// The statement must be prepared before it can be passed to optimize function.
// We pass InfoSchema instead of getting from Context in case it is changed after resolving name.
func Prepare(is infoschema.InfoSchema, ctx context.Context, node ast.Node) error {
ast.SetFlag(node)
if err := Preprocess(node, is, ctx); err != nil {
return errors.Trace(err)
}
if err := Validate(node, true); err != nil {
return errors.Trace(err)
}
return nil
}
// Optimizer error codes.
const (
CodeOneColumn terror.ErrCode = 1
CodeSameColumns terror.ErrCode = 2
CodeMultiWildCard terror.ErrCode = 3
CodeUnsupported terror.ErrCode = 4
CodeInvalidGroupFuncUse terror.ErrCode = 5
CodeIllegalReference terror.ErrCode = 6
)
// Optimizer base errors.
var (
ErrOneColumn = terror.ClassOptimizer.New(CodeOneColumn, "Operand should contain 1 column(s)")
ErrSameColumns = terror.ClassOptimizer.New(CodeSameColumns, "Operands should contain same columns")
ErrMultiWildCard = terror.ClassOptimizer.New(CodeMultiWildCard, "wildcard field exist more than once")
ErrUnSupported = terror.ClassOptimizer.New(CodeUnsupported, "unsupported")
ErrInvalidGroupFuncUse = terror.ClassOptimizer.New(CodeInvalidGroupFuncUse, "Invalid use of group function")
ErrIllegalReference = terror.ClassOptimizer.New(CodeIllegalReference, "Illegal reference")
)
func init() {
mySQLErrCodes := map[terror.ErrCode]uint16{
CodeOneColumn: mysql.ErrOperandColumns,
CodeSameColumns: mysql.ErrOperandColumns,
CodeMultiWildCard: mysql.ErrParse,
CodeInvalidGroupFuncUse: mysql.ErrInvalidGroupFuncUse,
CodeIllegalReference: mysql.ErrIllegalReference,
}
terror.ErrClassToMySQLCodes[terror.ClassOptimizer] = mySQLErrCodes
}