Zachary Tong 50c65d05ba Move bucket reduction from Bucket to the InternalAgg (#45566)
The current idiom is to have the InternalAggregator find all the
buckets sharing the same key, put them in a list, get the first bucket
and ask that bucket to reduce all the buckets (including itself).

This a somewhat confusing workflow, and feels like the aggregator should
be reducing the buckets (since the aggregator owns the buckets), rather
than asking one bucket to do all the reductions.

This commit basically moves the `Bucket.reduce()` method to the
InternalAgg and renames it `reduceBucket()`.  It also moves the
`createBucket()` (or equivalent) method from the bucket to the
InternalAgg as well.
2019-08-16 13:59:00 -04:00
..