[release-17.0] Fix a number of encoding issues when evaluating expressions with the evalengine (#13509)

[vitess-bot]

Description

This is a backport of #13509

[vitess-bot]

Review Checklist

Hello reviewers! 👋 Please follow this checklist when reviewing this Pull Request.

General

• Ensure that the Pull Request has a descriptive title.
• If this is a change that users need to know about, please apply the release notes (needs details) label so that merging is blocked unless the summary release notes document is included.
• If a test is added or modified, there should be a documentation on top of the test to explain what the expected behavior is what the test does.

If a new flag is being introduced:

• Is it really necessary to add this flag?
• Flag names should be clear and intuitive (as far as possible)
• Help text should be descriptive.
• Flag names should use dashes (-) as word separators rather than underscores (_).

If a workflow is added or modified:

• Each item in Jobs should be named in order to mark it as required.
• If the workflow should be required, the maintainer team should be notified.

Bug fixes

• There should be at least one unit or end-to-end test.
• The Pull Request description should include a link to an issue that describes the bug.

Non-trivial changes

• There should be some code comments as to why things are implemented the way they are.

New/Existing features

• Should be documented, either by modifying the existing documentation or creating new documentation.
• New features should have a link to a feature request issue or an RFC that documents the use cases, corner cases and test cases.

Backward compatibility

• Protobuf changes should be wire-compatible.
• Changes to _vt tables and RPCs need to be backward compatible.
• vtctl command output order should be stable and awk-able.
• RPC changes should be compatible with vitess-operator
• If a flag is removed, then it should also be removed from VTop, if used there.

[vitess-bot]

Hello @dbussink, there are conflicts in this backport.

Please address them in order to merge this Pull Request. You can execute the snippet below to reset your branch and resolve the conflict manually.

Make sure you replace origin by the name of the vitessio/vitess remote

git fetch --all
gh pr checkout 13551 -R vitessio/vitess
git reset --hard origin/release-17.0
git cherry-pick -m 1 694ffe8928dca4c89e0e55b008ed470e1afd44b5

[harshit-gangal]

I did not review the original PR, but it is a backport of the PR on main and fixing bugs with the evaluation engine. Hence approving it.

[deepthi]

This is a huge change to merge to a maintenance release. The risk is that we unintentionally break something.
I'm actually less worried about query serving functionality itself, but I notice two things.

• The original PR was not reviewed by @rohit-nayak-ps / @mattlord for the vreplication side of things.
• We did not benchmark it
  Let's do these two things and then maybe it'll be fine to back port.

[arewefastyet]

Hello! 👋

This Pull Request is now handled by arewefastyet. The current HEAD and future commits will be benchmarked.

You can find the performance comparison on the arewefastyet website.

[mattlord]

I'm good with the backport for VReplication. This should help with VDiffs. We're adding a couple of small (expected) fields in the querypb.Result related fields so I don't expect any noticeable performance impact.

[dbussink]

• We did not benchmark it
  Let's do these two things and then maybe it'll be fine to back port.

These things are looking good as well. Going to discard the change requested and get this merged then!

Comments have been addressed.