[Doc]Update Sql_faq.md

[Johnsonginati]

Fix the description about alter table

Why I'm doing:

What I'm doing:

Fixes #issue

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• [x ] Doc
• Tool

Does this PR entail a change in behavior?

• Yes, this PR will result in a change in behavior.
• No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• Interface/UI changes: syntax, type conversion, expression evaluation, display information
• Parameter changes: default values, similar parameters but with different default values
• Policy changes: use new policy to replace old one, functionality automatically enabled
• Feature removed
• Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• I have added test cases for my bug fix or my new feature
• This pr needs user documentation (for new or modified features or behaviors)
  • I have added documentation for my new feature or new function
• This is a backport pr

Bugfix cherry-pick branch check:

• I have checked the version labels which the pr will be auto-backported to the target branch
  • 3.4
  • 3.3
  • 3.2
  • 3.1
  • 3.0

[github-actions]

[Java-Extensions Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[github-actions]

[FE Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[github-actions]

[BE Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[EsoragotoSpirit]

Hi @Johnsonginati, thank you for your interest in our documentation. I have discussed this with our engineering team and they believe the original text is correct. Loading data during Schema Change will indeed affect the performance of the Schema Change, so we decided to close this PR. But you are always welcome to contribute to StarRocks documentation if you identify any issues! Have a good day!