Reduce segment bitmap size for the DMFile is partly ingested into stable layer
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component/storage
type/enhancement
- Dominant language
- C++
- Stars
- 1k
- Forks
- 423
- Avg merge
- 1d 15h
- Merged PRs (30d)
- 24
Description
Enhancement
As the test result (https://github.com/pingcap/tiflash/pull/9531) show, if a segment range is [0, 100) with a dmfile range is [0, 200). The segment mvcc bitmap contains the rows that is not valid for the segment range. This causes more memory and CPU.
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the segment MVCC bitmap handling shown in the PR 9531 diff at lines 522-558, using the issue's [0,100) segment and [0,200) DMFile example. The work is done when bitmap entries outside the segment range are no longer retained and the related memory and CPU overhead is reduced.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- databases
- Issue type
- Feature
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 38/100