Do not multiply AggregateRandom in JOINs

[frouioui]

Description

This Pull Request fixes the issue described in #11625. When pushing aggregation on a join, we were skipping the multiplication of results for min and max aggregations, however, we also need to skip the multiplication for random aggregations. Random aggregations simply need to get the column form one of the join's sides without multiplying it to the other side of the join.

Related Issue(s)

• Fixes Bug Report: vitess generates corrupted results on cross keyspace non full group by queries #11625.

Checklist

• "Backport me!" label has been added if this change should be backported
• Tests were added or are not required
• Documentation was added or is not required

[vitess-bot]

Review Checklist

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

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[arthurschreiber]

❤️

[tokikanno]

@frouioui : A quick question about AggregateRandom, does that mean we'll get random rows from non full group by queries?

BTW: 你會說中文? :-P

[frouioui]

A quick question about AggregateRandom, does that mean we'll get random rows from non full group by queries?

@tokikanno, the AggregateRandom does not apply a random function to the result, it simply takes the first row that MySQL returns. The results of the AggregateRandom will not be "flaky". You can see in the following code snippet how the engine primitive AggregateRandom is used:

https://github.com/planetscale/vitess/blob/adeccd2ae1e5b34da0da2fbf89debdc5ccefde2c/go/vt/vtgate/engine/ordered_aggregate.go#L531-L532

BTW: 你會說中文? :-P

我会一点点 不过我的中文不好 我的大学在北京

[frouioui]

@tokikanno, regarding doing a patch release: we will wait until at least the 3rd week of November to do a patch release. Since we recently released v15.0.0 we want to wait until we get more bug fixes.

[frouioui]

@systay, you added the release notes (needs details) label. I have modified the release notes for all current versions of v14 and v15 to include the known issue, and modified v16's release summary to include a note concerning this fix. I'll let you re-review and unlabel the PR if everything looks good.

[deepthi]

👍 on the release notes changes.

[vitess-bot]

I was unable to backport this Pull Request to the following branches: release-14.0, release-15.0.