// 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, // See the License for the specific language governing permissions and // limitations under the License. package aggfuncs import ( "github.com/pingcap/tidb/sessionctx" "github.com/pingcap/tidb/util/chunk" ) type cumeDist struct { baseAggFunc rowComparer } type partialResult4CumeDist struct { curIdx int lastRank int rows []chunk.Row } func (r *cumeDist) AllocPartialResult() PartialResult { return PartialResult(&partialResult4CumeDist{}) } func (r *cumeDist) ResetPartialResult(pr PartialResult) { p := (*partialResult4CumeDist)(pr) p.curIdx = 0 p.lastRank = 0 p.rows = p.rows[:0] } func (r *cumeDist) UpdatePartialResult(sctx sessionctx.Context, rowsInGroup []chunk.Row, pr PartialResult) error { p := (*partialResult4CumeDist)(pr) p.rows = append(p.rows, rowsInGroup...) return nil } func (r *cumeDist) AppendFinalResult2Chunk(sctx sessionctx.Context, pr PartialResult, chk *chunk.Chunk) error { p := (*partialResult4CumeDist)(pr) numRows := len(p.rows) for p.lastRank < numRows && r.compareRows(p.rows[p.curIdx], p.rows[p.lastRank]) == 0 { p.lastRank++ } p.curIdx++ chk.AppendFloat64(r.ordinal, float64(p.lastRank)/float64(numRows)) return nil }