// 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/expression" "github.com/pingcap/tidb/sessionctx" "github.com/pingcap/tidb/util/chunk" ) type rank struct { baseAggFunc isDense bool rowComparer } type partialResult4Rank struct { curIdx int64 lastRank int64 rows []chunk.Row } func (r *rank) AllocPartialResult() PartialResult { return PartialResult(&partialResult4Rank{}) } func (r *rank) ResetPartialResult(pr PartialResult) { p := (*partialResult4Rank)(pr) p.curIdx = 0 p.lastRank = 0 p.rows = p.rows[:0] } func (r *rank) UpdatePartialResult(sctx sessionctx.Context, rowsInGroup []chunk.Row, pr PartialResult) error { p := (*partialResult4Rank)(pr) p.rows = append(p.rows, rowsInGroup...) return nil } func (r *rank) AppendFinalResult2Chunk(sctx sessionctx.Context, pr PartialResult, chk *chunk.Chunk) error { p := (*partialResult4Rank)(pr) p.curIdx++ if p.curIdx == 1 { p.lastRank = 1 chk.AppendInt64(r.ordinal, p.lastRank) return nil } if r.compareRows(p.rows[p.curIdx-2], p.rows[p.curIdx-1]) == 0 { chk.AppendInt64(r.ordinal, p.lastRank) return nil } if r.isDense { p.lastRank++ } else { p.lastRank = p.curIdx } chk.AppendInt64(r.ordinal, p.lastRank) return nil } type rowComparer struct { cmpFuncs []chunk.CompareFunc colIdx []int } func buildRowComparer(cols []*expression.Column) rowComparer { rc := rowComparer{} rc.colIdx = make([]int, 0, len(cols)) rc.cmpFuncs = make([]chunk.CompareFunc, 0, len(cols)) for _, col := range cols { cmpFunc := chunk.GetCompareFunc(col.RetType) if cmpFunc == nil { continue } rc.cmpFuncs = append(rc.cmpFuncs, chunk.GetCompareFunc(col.RetType)) rc.colIdx = append(rc.colIdx, col.Index) } return rc } func (rc *rowComparer) compareRows(prev, curr chunk.Row) int { for i, idx := range rc.colIdx { res := rc.cmpFuncs[i](prev, idx, curr, idx) if res != 0 { return res } } return 0 }