98 lines
2.6 KiB
Go
98 lines
2.6 KiB
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/pkg/expression"
|
|
"github.com/pingcap/tidb/pkg/util/chunk"
|
|
)
|
|
|
|
const (
|
|
// DefPartialResult4LeadLagSize is the size of partialResult4LeadLag
|
|
DefPartialResult4LeadLagSize = int64(unsafe.Sizeof(partialResult4LeadLag{}))
|
|
)
|
|
|
|
type baseLeadLag struct {
|
|
baseAggFunc
|
|
valueEvaluator // TODO: move it to partial result when parallel execution is supported.
|
|
|
|
defaultExpr expression.Expression
|
|
offset uint64
|
|
}
|
|
|
|
type partialResult4LeadLag struct {
|
|
rows []chunk.Row
|
|
curIdx uint64
|
|
}
|
|
|
|
func (*baseLeadLag) AllocPartialResult() (pr PartialResult, memDelta int64) {
|
|
return PartialResult(&partialResult4LeadLag{}), DefPartialResult4LeadLagSize
|
|
}
|
|
|
|
func (*baseLeadLag) ResetPartialResult(pr PartialResult) {
|
|
p := (*partialResult4LeadLag)(pr)
|
|
p.rows = p.rows[:0]
|
|
p.curIdx = 0
|
|
}
|
|
|
|
func (*baseLeadLag) UpdatePartialResult(_ AggFuncUpdateContext, rowsInGroup []chunk.Row, pr PartialResult) (memDelta int64, err error) {
|
|
p := (*partialResult4LeadLag)(pr)
|
|
p.rows = append(p.rows, rowsInGroup...)
|
|
memDelta += int64(len(rowsInGroup)) * DefRowSize
|
|
return memDelta, nil
|
|
}
|
|
|
|
type lead struct {
|
|
baseLeadLag
|
|
}
|
|
|
|
func (v *lead) AppendFinalResult2Chunk(sctx AggFuncUpdateContext, pr PartialResult, chk *chunk.Chunk) error {
|
|
p := (*partialResult4LeadLag)(pr)
|
|
var err error
|
|
if p.curIdx+v.offset < uint64(len(p.rows)) {
|
|
_, err = v.evaluateRow(sctx, v.args[0], p.rows[p.curIdx+v.offset])
|
|
} else {
|
|
_, err = v.evaluateRow(sctx, v.defaultExpr, p.rows[p.curIdx])
|
|
}
|
|
if err != nil {
|
|
return err
|
|
}
|
|
v.appendResult(chk, v.ordinal)
|
|
p.curIdx++
|
|
return nil
|
|
}
|
|
|
|
type lag struct {
|
|
baseLeadLag
|
|
}
|
|
|
|
func (v *lag) AppendFinalResult2Chunk(sctx AggFuncUpdateContext, pr PartialResult, chk *chunk.Chunk) error {
|
|
p := (*partialResult4LeadLag)(pr)
|
|
var err error
|
|
if p.curIdx >= v.offset {
|
|
_, err = v.evaluateRow(sctx, v.args[0], p.rows[p.curIdx-v.offset])
|
|
} else {
|
|
_, err = v.evaluateRow(sctx, v.defaultExpr, p.rows[p.curIdx])
|
|
}
|
|
if err != nil {
|
|
return err
|
|
}
|
|
v.appendResult(chk, v.ordinal)
|
|
p.curIdx++
|
|
return nil
|
|
}
|