[BugFix] Fix SQL digest inconsistency between Follower and Leader (backport #67227)

[mergify]

Why I'm doing:

When the same SQL query is executed on Follower (forwarded to Leader) vs Leader (local execution), the Digest field in audit logs are inconsistent.

Root Cause:

• Follower calculates digest before AST analysis (TableName/SlotRef are not fully qualified)
• Leader calculates digest after AST analysis (TableName/SlotRef contain full catalog.db prefixes)
• The Analyzer.analyze() phase normalizes AST by filling catalog/db information into TableName and SlotRef objects
• Different AST states produce different string representations, leading to different MD5 digests

Example:

Follower: Digest=375dd0fba88b41ebe4a4eaa96f5cc692 | IsForwardToLeader=true
Leader:   Digest=2284580445ababd68839ad09e197ce63 | IsForwardToLeader=false

This inconsistency breaks digest-based query tracking, monitoring, and analysis.

What I'm doing:

Solution: Leader computes digest after analysis and returns it to Follower via Thrift RPC

Changes:

1. Thrift Protocol (FrontendService.thrift)

   • Added sql_digest field to TMasterOpResult structure

2. Leader Side (ConnectProcessor.java)

   • In doProxyExecute(): Compute SQL digest after AST analysis and set it in result.sql_digest
   • Leader does NOT generate its own audit log (proxy execution only)

3. Follower Side (ConnectProcessor.java)

   • Overloaded auditAfterExec() to accept optional digestFromLeader parameter
   • In handleQuery() and handleExecute(): Extract sql_digest from Leader's result
   • Use Leader's digest in audit log; fallback to local computation for non-forwarded queries

Flow:

Follower: parse → forward → receive result (with digest) → audit (use Leader's digest)
Leader:   parse → analyze → execute → compute digest → return result (no audit)

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
  • 4.0
  • 3.5
  • 3.4
  • 3.3

---

Note

Ensures consistent Digest in audit logs across leader/follower executions.

• Thrift: Add optional sql_digest to TMasterOpResult in FrontendService.thrift.
• Leader: In doProxyExecute(), compute digest post-analysis (computeStatementDigest) and set result.sql_digest.
• Follower: Overload auditAfterExec() to accept digestFromLeader; in handleQuery() and handleExecute(), extract sql_digest from leader result and pass to audit. Falls back to local digest when not forwarded or missing.
• Only sets audit digest when non-null; no other behavior changes.

^{Written by Cursor Bugbot for commit bf9c562. This will update automatically on new commits. Configure here.}

---

This is an automatic backport of pull request #67227 done by [Mergify](https://mergify.com).

[mergify]

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