diesel-rs/diesel

Experiment with generate `allow_columns_to_appear_in_same_group_by_clause!` via `diesel print-schema`

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#2,555 建立於 2020年11月5日

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 (2 留言) (5 反應) (0 負責人)Rust (12,054 star) (1,003 fork)batch import
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描述

#2549 introduced the allow_columns_to_appear_in_same_group_by_clause! macro that allows you to use more than one column in your group by clause. It opted not to generate a call to this macro for all columns in the schema via diesel print-schema due to compile time concerns. I would like to see some experimentation and some concert numbers for the actual compile time impact of this. As I think that's a good first issue, I will writeup some steps for someone willing to work on this:

  1. Similar to allow_tables_in_same_query! here we want to generate a call to allow_columns_to_appear_in_same_group_by_clause!. All required data are contained in self.tables. We need to iterate over all tables and all columns for each table and generate the corresponding macro call there.
  2. Test the impact on compile time of the generated schema.
    • That means get/generate a database with a large number of tables and columns (probably something that has >1000 columns or so).
    • Generate a schema.rs with the change in 1. applied
    • Generate a schema.rs without the change in 1. applied
    • Check and writedown the from scratch debug and release compile time for both variants. Also the incremental compile time without any change to the schema.rs module (but to some other module) may be interesting.
  3. Comment those numbers here, discuss if they are a acceptable hit

貢獻者指南

技術棧
rust
領域
clidatabasetooling
議題類型
research
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。
3-5 days
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 Rust knowledgefamiliarity with diesel CLIcompile time benchmarking
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。
60
研究方向
The issue proposes generating a call to `allow columns to appear in same group by clause!` in `diesel print schema`. First, modify the code in `diesel cli/src/print schema.rs` (around line 158) to iterate over all tables and columns from `self.tables` and emit the macro call for each column. Second, create a database with many tables and columns (e.g., >1000 columns) to measure compile time impact. Generate `schema.rs` with and without the change, and record debug and release compile times, as well as incremental compile times. Finally, report the numbers and discuss acceptability.