Observed EPOCH_NOT_MATCH on several TiFlash versions
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component/storage
severity/moderate
type/bug
- Dominant language
- C++
- Stars
- 1k
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- Avg merge
- 1d 15h
- Merged PRs (30d)
- 24
Description
Bug Report
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1. Minimal reproduce step (Required)
[2023/10/23 16:11:35.113 +08:00] [INFO] [KVStore.cpp:385] ["Start to persist [region_id=11013 index=515476 table_id=2684 ver=465 conf_ver=13 state=Normal peer=id: 11018 store_id: 20 role: Learner], cache size: 0 bytes for `tryFlushRegionData `"] [thread_id=62]
[2023/10/23 16:11:44.319 +08:00] [WARN] [CoprocessorHandler.cpp:220] ["RegionException: region_id=11013, message: Region error EPOCH_NOT_MATCH(doCopLearnerRead)"] [source="Coprocessor, is_remote_read: true, start_ts: 445133279005245469, region_info: {11013, 13, 462}, resource_group: default"] [thread_id=145]
2. What did you expect to see? (Required)
3. What did you see instead (Required)
4. What is your TiFlash version? (Required)
Contributor guide
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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
Begin by tracing the EPOCH_NOT_MATCH log from CoprocessorHandler.cpp:220 and the preceding persistence message in KVStore.cpp:385. Reproduce the reported learner read with the supplied region details across the affected TiFlash versions, then confirm the cause and that the error no longer occurs in the same scenario.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- databases, distributed-systems
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 15/100