68 lines
1.9 KiB
Go
68 lines
1.9 KiB
Go
// Copyright 2019 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package aggfuncs
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import (
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"unsafe"
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"github.com/pingcap/tidb/sessionctx"
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"github.com/pingcap/tidb/util/chunk"
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)
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const (
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// DefPartialResult4CumeDistSize is the size of partialResult4CumeDist
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DefPartialResult4CumeDistSize = int64(unsafe.Sizeof(partialResult4CumeDist{}))
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)
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type cumeDist struct {
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baseAggFunc
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rowComparer
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}
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type partialResult4CumeDist struct {
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curIdx int
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lastRank int
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rows []chunk.Row
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}
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func (r *cumeDist) AllocPartialResult() (pr PartialResult, memDelta int64) {
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return PartialResult(&partialResult4CumeDist{}), DefPartialResult4CumeDistSize
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}
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func (r *cumeDist) ResetPartialResult(pr PartialResult) {
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p := (*partialResult4CumeDist)(pr)
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p.curIdx = 0
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p.lastRank = 0
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p.rows = p.rows[:0]
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}
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func (r *cumeDist) UpdatePartialResult(sctx sessionctx.Context, rowsInGroup []chunk.Row, pr PartialResult) (memDelta int64, err error) {
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p := (*partialResult4CumeDist)(pr)
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p.rows = append(p.rows, rowsInGroup...)
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memDelta += int64(len(rowsInGroup)) * DefRowSize
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return memDelta, nil
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}
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func (r *cumeDist) AppendFinalResult2Chunk(sctx sessionctx.Context, pr PartialResult, chk *chunk.Chunk) error {
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p := (*partialResult4CumeDist)(pr)
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numRows := len(p.rows)
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for p.lastRank < numRows && r.compareRows(p.rows[p.curIdx], p.rows[p.lastRank]) == 0 {
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p.lastRank++
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}
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p.curIdx++
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chk.AppendFloat64(r.ordinal, float64(p.lastRank)/float64(numRows))
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return nil
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}
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