pingcap/tidb

Dumpling will stuck while it's expect to fallback to LOCK TABLES when FTWRL blocking for a long time

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#56,838 opened on Oct 25, 2024

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good first issuetype/enhancement

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Description

Enhancement

in https://github.com/pingcap/tidb/pull/36576 I want to implement a fallback strategy. But in line 1420 dumpling does not use the context with timeout https://github.com/pingcap/tidb/blob/7ce5bd752f668b4037a25ded97752f3eca258100/dumpling/export/dump.go#L1409-L1422

So current behaviour is, when upstream reports error like unsupported statement for FLUSH TABLE WITH READ LOCK, dumplling will fallback to LOCK TABLES. When upstream supports it but due to active sessions or other reason FTWRL is blocking, dumpling will stuck.

Maybe in the latter case it's also acceptable to fallback?

Contributor guide

Research direction
Investigate the code at dumpling/export/dump.go line 1420 to understand why the context with timeout is not used in the FTWRL fallback path. Check the context usage around line 1409-1422 and consider adding a fallback to LOCK TABLES when FTWRL blocks.
Tech stack
go
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Go
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70