pingcap/tidb

executor: avoid joiner to copying data when filter rows

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#12,030 建立於 2019年9月4日

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help wantedsig/executiontype/enhancementtype/performance

描述

Feature Request

Is your feature request related to a problem? Please describe:

We can use the sel field in chunk.Chunk instead of copying data in baseJoiner.filter when filtering data in join executor

Describe the feature you'd like:

We can use the sel field in chunk.Chunk used in baseJoiner.filter

Describe alternatives you've considered:

Teachability, Documentation, Adoption, Migration Strategy:

貢獻者指南

技術棧
go
領域
backenddatabaseperformance
議題類型
feature
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
half day
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
stale
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
Basic knowledge of GoUnderstanding of TiDB's executorFamiliarity with chunk.Chunk and sel field
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
50
研究方向
Study the `baseJoiner.filter` function in `executor/joiner.go` and the `sel` field in `util/chunk/chunk.go`. Understand how data is currently copied and how using `sel` can avoid that. Implement the change to use `sel` in `filter`, ensuring no performance regressions. Add tests to verify correctness.
executor: avoid joiner to copying data when filter rows · pingcap/tidb#12030 | Good First Issue