ddl: check local file existence before resume checkpoint

[lance6716]

What problem does this PR solve?

Issue Number: close #53009

Problem Summary:

What changed and how does it work?

• use word "flushed"/"imported" to replace "local"/"global" to unify the terminology with lightning engine
• rename some methods
• remove FlushModeForceLocalAndCheckDiskQuota because it's not used
• use ctx to detect the closing of CheckpointManager and let other goroutine communications check the context
• add a tagged logger to CheckpointManager
• remove updating field because only one goroutine calls updateCheckpoint

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test

  • I checked and no code files have been changed.

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[lance6716]

/ok-to-test

[codecov]

Codecov Report

Attention: Patch coverage is 91.42857% with 12 lines in your changes missing coverage. Please review.

Project coverage is 74.2582%. Comparing base (b6435d1) to head (c7075ee).
Report is 1336 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #53072        +/-   ##
================================================
+ Coverage   72.0130%   74.2582%   +2.2451%     
================================================
  Files          1499       1508         +9     
  Lines        431223     437154      +5931     
================================================
+ Hits         310537     324623     +14086     
+ Misses       101378      92404      -8974     
- Partials      19308      20127       +819     

Flag	Coverage Δ
integration	49.0410% <87.1428%> (?)
unit	71.2347% <85.0000%> (+0.0197%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	53.9957% <ø> (ø)
parser	∅ <ø> (∅)
br	46.1946% <ø> (+7.8468%)	⬆️

[D3Hunter]

rest lgtm

[D3Hunter]

shouldn't we call it maxKeyImported, it means all keys < it are imported

[lance6716]

ChatGPT still prefer the minXXX

---

You
How to name a variable which means "all keys less than it are flushed, but the keys larger than it can be flushed or not flushed". And it's calculated from the minimum value of some concurrency worker's progress.

ChatGPT
You might consider naming the variable something descriptive yet succinct, like "minFlushedKey" or "flushThreshold". This would indicate that it represents the minimum key value up to which all keys are flushed, but keys larger than it might or might not be flushed depending on their status. Alternatively, you could name it "minFlushedProgressKey" to be more explicit about its relationship to progress.

Here's a breakdown of each potential name:

minFlushedKey: This name clearly indicates that it represents the minimum key value that has been flushed. It suggests that any keys smaller than this value are flushed, while those larger than it may or may not be flushed.
flushThreshold: This name implies that it's a point or level that determines when flushing occurs. It's like a threshold that, once reached, triggers the flushing of keys. "FlushThreshold" conveys that keys below this threshold are flushed, while those above it may or may not be.
minFlushedProgressKey: This name explicitly links the variable to progress and flushing. It suggests that it represents the minimum key based on the progress made, and keys less than or equal to this value are considered flushed.
Choose the name that best fits the context and naming conventions of your project. The most important thing is that the name is clear and understandable to anyone reading your code.

[D3Hunter]

i don't think minFlushedKey suggests that any keys smaller than this value are flushed, it only states that it's the min key that have flushed and any key before or after it may or may not flushed

And it's calculated from the minimum value of some concurrency worker's progress.

from this description, we can only got a name like min key of on-going task

[lance6716]

How about rename it to flushedKeyLowWatermark? I can do it in #52993

[D3Hunter]

lgtm

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: D3Hunter, tangenta

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• pkg/ddl/OWNERS [tangenta]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-07 07:59:06.853770748 +0000 UTC m=+948900.610906315: ☑️ agreed by tangenta.
• 2024-05-07 09:33:17.443170108 +0000 UTC m=+954551.200305679: ☑️ agreed by D3Hunter.

[lance6716]

/cherry-pick release-8.1

[ti-chi-bot]

@lance6716: new pull request created to branch release-8.1: #53083.

In response to this:

/cherry-pick release-8.1

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[wjhuang2016]

/cherry-pick release-7.5

[ti-chi-bot]

@wjhuang2016: new pull request created to branch release-7.5: #53577.

In response to this:

/cherry-pick release-7.5

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

In response to a cherrypick label: new pull request could not be created: failed to create pull request against pingcap/tidb#release-7.5 from head ti-chi-bot:cherry-pick-53072-to-release-7.5: status code 422 not one of [201], body: {"message":"Validation Failed","errors":[{"resource":"PullRequest","code":"custom","message":"A pull request already exists for ti-chi-bot:cherry-pick-53072-to-release-7.5."}],"documentation_url":"https://docs.github.com/rest/pulls/pulls#create-a-pull-request"}

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #57032.