[improvement] (deitlog) Skip edit log writing when global variable value unchanged

[heguanhui]

[improvement] (deitlog) Skip edit log writing when global variable value unchanged

Avoid unnecessary edit log writes when setting global variable to the same value. This reduces disk I/O and prevents edit log bloat.

The optimization adds a value comparison check before setting the variable and writing edit log, maintaining thread safety under existing wlock.

What problem does this PR solve?

Issue Number: close #xxx

Related PR: #xxx

Problem Summary:

Release note

None

Check List (For Author)

• Test

  • [ ] Unit Test
  • [ ] Manual test (add detailed scripts or steps below)

• Behavior changed:

  • [ ] No.

• Does this need documentation?

  • [ ] No.

Check List (For Reviewer who merge this PR)

• [ ] Confirm the release note
• [ ] Confirm test cases
• [ ] Confirm document
• [ ] Add branch pick label

[Thearas]

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Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
3. What features were added. Why was this function added?
4. Which code was refactored and why was this part of the code refactored?
5. Which functions were optimized and what is the difference before and after the optimization?