ddl: skip getting actual end key for each range in ingest mode (#54143)

[ti-chi-bot]

This is an automated cherry-pick of #54143

What problem does this PR solve?

Issue Number: close #45847, close #54147

Problem Summary: See #54147 (comment)

What changed and how does it work?

It is slow to get the actual end key of a range.

Previously, we introduce this for the reason that there may be mass writes during adding index, and the txn backfill workers cannot catch up with newly written row records. As a result, adding index never complete.

However, this can hardly happen in ingest mode:

1. in write&ingest step, we use coprocessor instead of kv.scan to read table data, backfill workers are 10X speeded up.
2. in merge temp-index step, index records are relatively small, and we have double-write mechanism to avoid temp index data grow infinitely.

This PR skips getting actual end key for each range in ingest mode.

Other changes include:

• Refine the usage of splitTableRanges.
• Extract getActualEndKey to a function.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

  mysql> alter table usertable add index test_idx(FIELD0);
  Query OK, 0 rows affected (2 min 32.11 sec)
  
  mysql> alter table usertable add index test_idx(FIELD0);
  Query OK, 0 rows affected (2 min 28.35 sec)
  
  mysql> alter table usertable add index test_idx(FIELD0);
  Query OK, 0 rows affected (2 min 33.82 sec)
  
  mysql> alter table usertable add index test_idx(FIELD0);
  Query OK, 0 rows affected (2 min 29.74 sec)
  

• 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

[codecov]

Codecov Report

Attention: Patch coverage is 79.65368% with 47 lines in your changes missing coverage. Please review.

Please upload report for BASE (release-7.5@4b4b177). Learn more about missing BASE report.

Additional details and impacted files

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##             release-7.5     #56748   +/-   ##
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Flag	Coverage Δ
unit	72.6202% <79.6536%> (?)

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

Components	Coverage Δ
dumpling	52.9400% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	54.5113% <0.0000%> (?)

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lance6716, tangenta

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• pkg/ddl/OWNERS [tangenta]
• pkg/resourcemanager/OWNERS [lance6716,tangenta]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-12-06 07:50:24.771595433 +0000 UTC m=+1400412.391249949: ☑️ agreed by tangenta.
• 2024-12-10 10:20:04.537537929 +0000 UTC m=+347394.626340474: ☑️ agreed by lance6716.

[tangenta]

/retest

[ti-chi-bot]

@ti-chi-bot: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
idc-jenkins-ci-tidb/mysql-test	bd8d83e	link	unknown	/test mysql-test

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[tangenta]

/retest