release-24.1: sql: implement generic query plans

[mgartner]

Backport:

• 1/1 commits from "sql: add plan_cache_mode session setting" (#125708)
• 2/2 commits from "opt: add ConvertSelectWithPlaceholdersToJoin exploration rule" (#125795)
• 2/2 commits from "opt: improve stats for filters with placeholder equalities" (#125808)
• 1/1 commits from "opt: add generic query plan tests with partial indexes" (#125871)
• 3/3 commits from "sql: implement plan_cache_mode=force_generic_plan" (#126528)
• 1/2 commits from "sql: implement plan_cache_mode=auto" (#126863)
• 2/2 commits from "opt: optimize generic query plans with stable expressions" (#125814)
• 1/1 commits from "sql: require an enterprise license to use generic query plans" (#127214)
• 1/1 commits from "sql: add telemetry counters for generic query plans" (#127897)

Please see individual PRs for details.

/cc @cockroachdb/release

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Release justification: New feature gated behind session setting.

[blathers-crl[bot]]

Thanks for opening a backport.

Please check the backport criteria before merging:

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[blathers-crl[bot]]

Your pull request contains more than 1000 changes. It is strongly encouraged to split big PRs into smaller chunks.

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[cockroach-teamcity]

This change is 

[mgartner]

I know this PR was big. I thought backporting everything in bulk would be nice, but I'm happy to backport one PR at a time if that's easier on everyone else.

[rytaft]

Great work!! I didn't review all the code in detail since I think the original PR was reviewed carefully, but I did add a couple suggestions for things that might need a setting.

[mgartner]

@rytaft I don't see your suggestions. Did you forget to publish them?

[mgartner]

I've added one of the commits from #129050.

[mgartner]

pkg/sql/plan_opt.go line 575 at r9 (raw file):

Previously, DrewKimball (Drew Kimball) wrote…

Would it ever be possible to have a stale fully optimized plan and non-stale generic plan? Or similar for a generic plan and a normalized plan.

Yes, I think both are possible. I intended to handle these cases with this logic. Is there something wrong you see?

[mgartner]

pkg/sql/plan_opt.go line 575 at r9 (raw file):

Previously, DrewKimball (Drew Kimball) wrote…

Well if we do have a stale fully-optimized plan, shouldn't we return nil and build a new one, rather than resorting to a generic memo?

That should never be possible. If the query has no placeholders or stable functions, then we'll never generate a generic memo, so it'll always be nil.

I think a lot of this confusion will be cleared up as I refactor this logic such that all fully-optimized plans are "generic", and the other cached plan is "normalized" or a "base" memo that still needs to be optimized. The main reason I didn't structure things like that form the get-go is because it would have made these backports more risky.

[mgartner]

TFTRs!