pingcap / pingcap/tiflash

Write amplification caused by delete range

Open
#1,245 0 comments 0 reactions 1 assignee View on GitHub

@flowbehappy is already working on this.

Since Nov 25, 2020.

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

Description

Currently, we trigger a delta merge task after a segment has more than 2 delete ranges. The basic idea is to speed up the scan speed since the more delete ranges in Delta layer, the slower speed.

But it causes frequency Delta Merge operations, especially when TiFlash is receiving many snapshots. The better idea is only relying on the delete entries (how many rows got deleted). So we need to remove the trigger logic by "2 delete ranges".

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.

Assessment

This issue has not been assessed yet.

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.