pingcap / pingcap/tiflash

Support RightOuterSemi/RightOuterAntiSemi join

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type/enhancement
Dominant language
C++
Stars
1k
Forks
423
Avg merge
1d 15h
Merged PRs (30d)
24

Description

Enhancement

Currently, for lefter outer semi/antiSemi joins with other conditions, only original right table can be used as build table. Thus tiflash only supports LeftOuterSemi, LeftOuterAntiSemi joins.
This would introduce performance issue when original left table size is much smaller than original right table, in which case using original left table as build table would be a better choice.

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

The issue names no files or tests. Start by locating the existing LeftOuterSemi and LeftOuterAntiSemi join implementation and the join tests, then determine the design needed for RightOuterSemi and RightOuterAntiSemi with other conditions. Done means both right-oriented join types are supported and their performance behavior is covered by tests.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
database
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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