fix: add missing MySQL 8.4 keywords

[dbussink]

Takes #17525 and adds the fix for the change here as requested by @L3o-pold.

Related Issue(s)

Fixes #17523

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.71%. Comparing base (db4fca3) to head (aae53bc).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #17538      +/-   ##
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+ Coverage   67.68%   67.71%   +0.02%     
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  Files        1584     1584              
  Lines      254630   254717      +87     
==========================================
+ Hits       172356   172472     +116     
+ Misses      82274    82245      -29     

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[GrahamCampbell]

Probably makes sense to use the MySQL 9.0 output. It's almost identical, except for the fact that it also has Vector. AKA, it's exactly what we're aiming to support at the moment.

[dbussink]

@GrahamCampbell As mentioned in #17525 I'd like to stay with this here for now and look at this separately later.

[dbussink]

Relevant for reviewers here, this is from #17525 (comment):

---

We should not add the keywords here to the Vitess side of reserved keywords. The reason is the following. The original bug here you reported is that the keyword is not escaped in the SQL that Vitess generates again. That is indeed since it doesn't know these as keywords.

But we don't need reserved keywords here, they can be non-reserved keywords. This is because these words won't cause any conflict in the grammar, so they don't need to be reserved. This way we don't break existing queries that use these keywords also for people who are not on MySQL 8.4, as we only have one grammar for all MySQL versions.

In the future we might also need to make it reserved once we add the actual parsing rules that use these keywords, but that would be a better time to also make them reserved because that at point there's actual feature support for something where it's needed.

---

[L3o-pold]

@dbussink can we backport this to 21.x ?

[dbussink]

@dbussink can we backport this to 21.x ?

I don't have a super strong opinion, but afaik the policy is to not back port fixes for experimentally supported things like 8.4 and that it will be part of the next release then. Also cc @deepthi for this question.

[L3o-pold]

My guess was that 8.4 was not experimental instead of 9.0 :(

Vitess has experimental MySQL 8.4 support with the same limitations as 8.0.*.

but I was wrong...

[GrahamCampbell]

My vote would be to not backport, and to add a changelog entry to v22 saying improved MySQL 8.4 support.

[L3o-pold]

I think it's a waste to wait a major release to fix something we already support as experimental. v22 will be the place to add Vitess docker image with MySQL 8.4 (by default?)

[dbussink]

v22 will be the place to add Vitess docker image with MySQL 8.4 (by default?)

We should add it, but not make it the default yet. I think we want to have it bake for a bit longer before it's the default.

[GrahamCampbell]

I'm curious what features you need from MySQL 8.4 that are not present in 8.0.40?

[L3o-pold]

none, just wanted to upgrade to an LTS version

[GrahamCampbell]

MySQL 8.0 is also LTS.

[GrahamCampbell]

And Vitess 21 will be EOL before MySQL 8.0 is.

[L3o-pold]

So it's nice to update to the latest LTS version, I don't see the debate here...

[GrahamCampbell]

The point is that it does not make sense to backport this to Vitess 21.

[L3o-pold]

asking what feature we want to use in MySQL 8.4 to prove that backporting this in Vitess 21 make no sens to me ;)

[GrahamCampbell]

I was establishing if there was a reason you needed to use 8.4. None was provided. If there was a good reason that might apply widely, then there could be a compelling case for backport.

[L3o-pold]

If you need argument on why upgrading see: https://docs.percona.com/percona-server/8.4/upgrade.html