tidb row_number 源码
tidb row_number 代码
文件路径：/executor/aggfuncs/row_number.go
// Copyright 2019 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,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package aggfuncs
import (
"unsafe"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/util/chunk"
)
const (
// DefPartialResult4RowNumberSize is the size of partialResult4RowNumberSize
DefPartialResult4RowNumberSize = int64(unsafe.Sizeof(partialResult4RowNumber{}))
)
type rowNumber struct {
baseAggFunc
}
type partialResult4RowNumber struct {
curIdx int64
}
func (rn *rowNumber) AllocPartialResult() (pr PartialResult, memDelta int64) {
return PartialResult(&partialResult4RowNumber{}), DefPartialResult4RowNumberSize
}
func (rn *rowNumber) ResetPartialResult(pr PartialResult) {
p := (*partialResult4RowNumber)(pr)
p.curIdx = 0
}
func (rn *rowNumber) UpdatePartialResult(sctx sessionctx.Context, rowsInGroup []chunk.Row, pr PartialResult) (memDelta int64, err error) {
return 0, nil
}
func (rn *rowNumber) AppendFinalResult2Chunk(sctx sessionctx.Context, pr PartialResult, chk *chunk.Chunk) error {
p := (*partialResult4RowNumber)(pr)
p.curIdx++
chk.AppendInt64(rn.ordinal, p.curIdx)
return nil
}
var _ SlidingWindowAggFunc = &rowNumber{}
func (rn *rowNumber) Slide(sctx sessionctx.Context, getRow func(uint64) chunk.Row, lastStart, lastEnd uint64, shiftStart, shiftEnd uint64, pr PartialResult) error {
return nil
}
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