pingcap / pingcap/tiflash

Support prefetch HashSet for count(distinct)

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

Description

Enhancement

similar to https://github.com/pingcap/tiflash/issues/9680, but prefetch HashSet is good for count(distinct)

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, tests, or entry points. Start by reading the linked TiFlash issue 9680 and then locate the count(distinct) implementation and its existing HashSet handling; done means prefetch support is implemented and validated for count(distinct).

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
databases, performance
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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