Fix incorrect string value when doing int_handle.toNext

[breezewish]

Signed-off-by: Wish [email protected]

What problem does this PR solve?

Issue Number: close #6699

Problem Summary:

Consider an Int Handle in variable foo which is 0xCCAB. It is encoded as { 80 00 00 00 00 00 CC AB } in bytes.

In #6538:

foo.toNext:       int_value = 0xCCAC, bytes_value = { 80 00 00 00 00 00 CC AB 00 }
foo.toPrefixNext: int_value = 0xCCAC, bytes_value = { 80 00 00 00 00 00 CC AC }

The implementation of toNext() is incorrect because it violates the rule that the int_value and bytes_value should be matching.

Let's see what will happen when this rule is not respected:

• Consider we construct a new Int Handle in variable bar from int 0xCCAC. It will be built as int_value = 0xCCAC, bytes_value = { 80 00 00 00 00 00 CC AC }. Now bar and foo'content are not identical any more.

• The max, min and several other basic functions are implemented by comparing bytes values:

  inline const RowKeyValue & max(const RowKeyValue & a, const RowKeyValue & b)
  {
      return a.value->compare(*b.value) >= 0 ? a : b;
  }
  
  inline const RowKeyValue & min(const RowKeyValue & a, const RowKeyValue & b)
  {
      return a.value->compare(*b.value) < 0 ? a : b;
  }
  
  inline bool none() const
  {
      return start.value->compare(*end.value) >= 0;
  }
  
  inline bool intersect(const RowKeyRange & other) const
  {
      return max(other.start, start).value->compare(*min(other.end, end).value) < 0;
  }
  
  bool operator==(const RowKeyRange & rhs) const
  {
      return start.value->compare(*rhs.start.value) == 0 && end.value->compare(*rhs.end.value) == 0;
  }

• As a result, buggy things happen, like foo.toNext() != bar. Everything related with equality or orders may have wrong results.

What is changed and how it works?

Encode Int handle using toPrefixNext() in toNext(), so that the int_value and bytes_value are still matching.

Check List

Tests

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

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

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• JaySon-Huang
• hehechen

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[breezewish]

/release

[breezewish]

/build

[JaySon-Huang]

can you elaborate more about why this cause data lost in #6699?

[breezewish]

can you elaborate more about why this cause data lost in #6699?

I updated the PR description, please take a look again, thanks!

[breezewish]

/run-all-tests

[hehechen]

It's confusing. EXPECT_EQ(v1, v0_next) is better ?

[JaySon-Huang]

lgtm

[breezewish]

/merge

[ti-chi-bot]

@breezewish: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 97cc654

[ti-chi-bot]

@breezewish: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

trigger some heavy tests which will not run always when PR updated.

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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.

[JaySon-Huang]

/rebuild

[breezewish]

/run-integration-test