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// Copyright 2017 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 aggregation
import (
"github.com/pingcap/errors"
"github.com/pingcap/parser/ast"
"github.com/pingcap/tidb/expression"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/sessionctx/stmtctx"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tipb/go-tipb"
)
// AggFuncToPBExpr converts aggregate function to pb.
func AggFuncToPBExpr(sc *stmtctx.StatementContext, client kv.Client, aggFunc *AggFuncDesc) *tipb.Expr {
if aggFunc.HasDistinct {
// do nothing and ignore aggFunc.HasDistinct
}
if len(aggFunc.OrderByItems) > 0 {
return nil
}
pc := expression.NewPBConverter(client, sc)
var tp tipb.ExprType
switch aggFunc.Name {
case ast.AggFuncCount:
tp = tipb.ExprType_Count
case ast.AggFuncApproxCountDistinct:
tp = tipb.ExprType_ApproxCountDistinct
case ast.AggFuncFirstRow:
tp = tipb.ExprType_First
case ast.AggFuncGroupConcat:
tp = tipb.ExprType_GroupConcat
case ast.AggFuncMax:
tp = tipb.ExprType_Max
case ast.AggFuncMin:
tp = tipb.ExprType_Min
case ast.AggFuncSum:
tp = tipb.ExprType_Sum
case ast.AggFuncAvg:
tp = tipb.ExprType_Avg
case ast.AggFuncBitOr:
tp = tipb.ExprType_Agg_BitOr
case ast.AggFuncBitXor:
tp = tipb.ExprType_Agg_BitXor
case ast.AggFuncBitAnd:
tp = tipb.ExprType_Agg_BitAnd
case ast.AggFuncVarPop:
tp = tipb.ExprType_VarPop
case ast.AggFuncJsonObjectAgg:
tp = tipb.ExprType_JsonObjectAgg
case ast.AggFuncStddevPop:
tp = tipb.ExprType_StddevPop
case ast.AggFuncVarSamp:
tp = tipb.ExprType_VarSamp
case ast.AggFuncStddevSamp:
tp = tipb.ExprType_StddevSamp
}
if !client.IsRequestTypeSupported(kv.ReqTypeSelect, int64(tp)) {
return nil
}
children := make([]*tipb.Expr, 0, len(aggFunc.Args))
for _, arg := range aggFunc.Args {
pbArg := pc.ExprToPB(arg)
if pbArg == nil {
return nil
}
children = append(children, pbArg)
}
return &tipb.Expr{Tp: tp, Children: children, FieldType: expression.ToPBFieldType(aggFunc.RetTp)}
}
// PBExprToAggFuncDesc converts pb to aggregate function.
func PBExprToAggFuncDesc(ctx sessionctx.Context, aggFunc *tipb.Expr, fieldTps []*types.FieldType) (*AggFuncDesc, error) {
var name string
switch aggFunc.Tp {
case tipb.ExprType_Count:
name = ast.AggFuncCount
case tipb.ExprType_ApproxCountDistinct:
name = ast.AggFuncApproxCountDistinct
case tipb.ExprType_First:
name = ast.AggFuncFirstRow
case tipb.ExprType_GroupConcat:
name = ast.AggFuncGroupConcat
case tipb.ExprType_Max:
name = ast.AggFuncMax
case tipb.ExprType_Min:
name = ast.AggFuncMin
case tipb.ExprType_Sum:
name = ast.AggFuncSum
case tipb.ExprType_Avg:
name = ast.AggFuncAvg
case tipb.ExprType_Agg_BitOr:
name = ast.AggFuncBitOr
case tipb.ExprType_Agg_BitXor:
name = ast.AggFuncBitXor
case tipb.ExprType_Agg_BitAnd:
name = ast.AggFuncBitAnd
default:
return nil, errors.Errorf("unknown aggregation function type: %v", aggFunc.Tp)
}
args, err := expression.PBToExprs(aggFunc.Children, fieldTps, ctx.GetSessionVars().StmtCtx)
if err != nil {
return nil, err
}
base := baseFuncDesc{
Name: name,
Args: args,
RetTp: expression.FieldTypeFromPB(aggFunc.FieldType),
}
base.WrapCastForAggArgs(ctx)
return &AggFuncDesc{
baseFuncDesc: base,
Mode: Partial1Mode,
HasDistinct: false,
}, nil
}