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executor: change the evaluation order of columns in Update and Insert statements (#57123) #58524

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This is an automated cherry-pick of #57123

What problem does this PR solve?

Issue Number: ref #56829

Problem Summary:

In the previous logic, when we use UPDATE or INSERT ON DUPLICATE, the new row will be generated in the following order:

  • Fill all the explicitly set columns.
  • Evaluate all auto-generated columns. For UPDATE and INSERT, they are evaluated in composeGeneratedColumns and doDupRowUpdate respectively.
  • Update on-update-now columns if necessary.

However, auto-generated columns may rely on the on-update-now columns to generate value. For example in #56829 (comment)

CREATE TABLE cache (
  cache_key varchar(512) NOT NULL,
  updated_at datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  expired_at datetime GENERATED ALWAYS AS (if(expires > 0, date_add(updated_at, interval expires second), date_add(updated_at, interval 99 year))) VIRTUAL,
  expires int(11),
  PRIMARY KEY (cache_key) /*T![clustered_index] CLUSTERED */,
  KEY idx_c_on_expired_at (expired_at)
);

expired_at is generated based on the latest timestamp value from updated_at. So we will get wrong expired_at value. Even worse, expired_at is the part of the index idx_c_on_expired_at. So querying data expired_at using index scan and full table scan will get different result, since in full table scan, expired_at is calculated in real-time.

This also explains #56829 (comment) why changing VIRTUAL to STORED will not yield such error, although this value itself is incorrect.

What changed and how does it work?

To address this problem, this PR refactor the logic of INSERT ON DUPLICATE and UPDATE. More specifically:

  • Move the evalation of auto-generated columns in updateRecord.
  • ForeignKey Check is also moved into updateRecord.
  • Extract errorHandler function for UPDATE and INSERT to handle error/warning in updateRecord.

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

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>
@ti-chi-bot ti-chi-bot added ok-to-test Indicates a PR is ready to be tested. release-note-none Denotes a PR that doesn't merit a release note. size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. type/cherry-pick-for-release-7.1 This PR is cherry-picked to release-7.1 from a source PR. labels Dec 25, 2024
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ti-chi-bot bot commented Dec 25, 2024

This cherry pick PR is for a release branch and has not yet been approved by triage owners.
Adding the do-not-merge/cherry-pick-not-approved label.

To merge this cherry pick:

  1. It must be approved by the approvers firstly.
  2. AFTER it has been approved by approvers, please wait for the cherry-pick merging approval from triage owners.

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ti-chi-bot bot commented Dec 25, 2024

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign lcwangchao for approval. For more information see the Code Review Process.

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@joechenrh
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/ok-to-test

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codecov bot commented Dec 26, 2024

Codecov Report

Attention: Patch coverage is 72.64957% with 64 lines in your changes missing coverage. Please review.

Please upload report for BASE (release-7.1@0a9f9c7). Learn more about missing BASE report.

Additional details and impacted files
@@               Coverage Diff                @@
##             release-7.1     #58524   +/-   ##
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  Coverage               ?   73.4723%           
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  Files                  ?       1213           
  Lines                  ?     382190           
  Branches               ?          0           
================================================
  Hits                   ?     280804           
  Misses                 ?      83448           
  Partials               ?      17938           

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