Implement appendCallerID feature in vtgate executor

[corbantek]

Description

• Added a new boolean flag appendCallerID to control the appending of CallerId username to queries.
• Updated the NewExecutor function to accept the appendCallerID parameter.
• Modified the newExecute method to conditionally append CallerId to the SQL query if the flag is enabled.

Related Issue(s)

• Feature Request: Append CallerID to all VTGate Queries (from HubSpot) #18636

Checklist

• "Backport to:" labels have been added if this change should be back-ported to release branches
• If this change is to be back-ported to previous releases, a justification is included in the PR description
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on CI?
• Documentation was added or is not required

Deployment Notes

[vitess-bot]

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[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 67.48%. Comparing base (58f753c) to head (5c6dea2).
⚠️ Report is 184 commits behind head on main.

Files with missing lines	Patch %	Lines
go/vt/vtgate/plan_execute.go	50.00%	2 Missing ⚠️
go/vt/vtgate/vtgate.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18635      +/-   ##
==========================================
- Coverage   67.50%   67.48%   -0.02%     
==========================================
  Files        1607     1608       +1     
  Lines      263527   263535       +8     
==========================================
- Hits       177890   177858      -32     
- Misses      85637    85677      +40     

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[sam-k3nny]

Is there a way of nudging this forward please? Etsy are also very interested in this change.

[harshit-gangal]

This can bloat the plan cache and more planner work for the prepared statement queries.
I would suggest we move this logic either in vttablet or add it directly as margin comments when we create the vcursol_impl object.

[harshit-gangal]

Have you looked at the vttablet flag queryserver-config-annotate-queries that enables writing caller ID as comments to the sql query before executing it on MySQL

[corbantek]

Have you looked at the vttablet flag queryserver-config-annotate-queries that enables writing caller ID as comments to the sql query before executing it on MySQL

My apologies on the delayed response, let me go investigate if this has equal parity with this PR...

[sam-k3nny]

The advantage of this approach, IIUC, is that is not based on an honour system. We can't always guarantee the caller will have added Caller ID to the comments. More often than not, when we want to identify the caller, it is because of unexpected requests. This approach ensures we have the caller if there are rogue requests.

Let me know if I've misunderstood anything though.

[github-actions]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

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[github-actions]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

• Push additional commits to the associated branch.
• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.