[Enhancement] Introduce SCHEDULE keyword as ASYNC synonym for MV refresh (backport #72329)

[mergify]

Why I'm doing:

What I'm doing:

the trigger framework keyword for scheduled refresh is renamed to SCHEDULE. ASYNC is preserved as a parser-level synonym so existing scripts continue to work; SHOW CREATE displays the new SCHEDULE keyword.

Production:

• Grammar: refreshSchemeDesc now accepts (ASYNC | SCHEDULE) as equivalent tokens for the scheduled refresh form. Both keywords are already declared in the lexer and listed as non-reserved.
• AstBuilder.visitRefreshSchemeDesc: branch on ASYNC || SCHEDULE; both produce the same AsyncRefreshSchemeDesc.
• MaterializedView.getMaterializedViewDdlStmt: emit "SCHEDULE" in place of "ASYNC" for MaterializedViewRefreshType.ASYNC. The persisted enum is unchanged; only the user-facing display is updated.

Tests:

• Add a synonym test (testAsyncIsSynonymForScheduleAndShowCreatePrefers Schedule) covering both keywords in CREATE and asserting SHOW CREATE output uses SCHEDULE.
• Update the parameterized refreshArgumentsList in ShowCreateMaterializedViewStmtTest from REFRESH ASYNC to REFRESH SCHEDULE so the SHOW CREATE round-trip assertion matches the new display.
• Update testAlterRefreshScheme to translate ASYNC→SCHEDULE when comparing the SHOW CREATE output of an ALTER REFRESH ASYNC ... statement.
• Update SQL integration R files where SHOW CREATE output appears (test_enable_mv, test_random_distribution) to expect SCHEDULE.

Fixes #issue

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• 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 pr needs auto generate documentation
• 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
  • 4.1
  • 4.0
  • 3.5
  • 3.4

---

This is an automatic backport of pull request #72329 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 112df75 has failed:

On branch mergify/bp/branch-4.1/pr-72329
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You are currently cherry-picking commit 112df75c36.
  (fix conflicts and run "git cherry-pick --continue")
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Changes to be committed:
	modified:   docs/en/sql-reference/sql-statements/materialized_view/ALTER_MATERIALIZED_VIEW.md
	modified:   docs/en/sql-reference/sql-statements/materialized_view/CREATE_MATERIALIZED_VIEW.md
	modified:   docs/ja/sql-reference/sql-statements/materialized_view/ALTER_MATERIALIZED_VIEW.md
	modified:   docs/ja/sql-reference/sql-statements/materialized_view/CREATE_MATERIALIZED_VIEW.md
	modified:   docs/zh/sql-reference/sql-statements/materialized_view/ALTER_MATERIALIZED_VIEW.md
	modified:   docs/zh/sql-reference/sql-statements/materialized_view/CREATE_MATERIALIZED_VIEW.md
	modified:   fe/fe-core/src/main/java/com/starrocks/catalog/MaterializedView.java
	modified:   fe/fe-core/src/main/java/com/starrocks/sql/parser/AstBuilder.java
	modified:   fe/fe-core/src/test/java/com/starrocks/analysis/AlterMaterializedViewTest.java
	modified:   fe/fe-core/src/test/java/com/starrocks/analysis/ShowCreateMaterializedViewStmtTest.java

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   fe/fe-grammar/src/main/antlr/com/starrocks/grammar/StarRocks.g4

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[mergify]

@mergify[bot]: Backport conflict, please reslove the conflict and resubmit the pr

[github-actions]

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🕒 Last updated: Wed, 29 Apr 2026 11:23:15 GMT