Improve aggregation documentation for multi-phase aggregation #11695
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Draft as it builds on #11627
Which issue does this PR close?
Part of #6937
Rationale for this change
As part of reviewing @korowa 's wonderful #11627 to improve multi-phase aggregation I want to document how it works a bit more (so it is easier to add the relevant support for other aggregates)
What changes are included in this PR?
Are these changes tested?
By docs CI
Are there any user-facing changes?
Just docs, no functional changes