This commit changes the channel iterators to use a double buffer
to reduce allocations. The caller of `Iterator.Next()` must copy
out the point before calling `Next()` again.
If a point had no tags at all and was asked for the subset of tags with
at least one key, it would return a new set of tags that was completely
empty. In contrast, if the point had any tags at all, it would return a
set of tags with the tag value being an empty string. This lead to
a point with no tags being treated differently than a point with at
least one tag.
Fixing this so the tag value will always be an empty string for
consistency. A missing tag should always be empty.
Fixes#6211.
In Go-land packages with the same name, e.g., internal, do not clash
with each other when they're in different parts of the project. However
with protobufs definitions will clash if they share the same package
name.
This commit renames the influxql protobuf package to `influxql` to
avoid a clash with a message definition in another protobuf package
called internal. Go package aliases allow us to continue to refer to the
internal package as `internal` rather than `influxql`.
This commit adds an `IteratorStats` that holds aggregate
iterator processing information. A method is also added to
`Iterator` to return the stats:
Stats() influxql.IteratorStats
The remote iterators will also emit their stats in the point
stream upon first connection, on a given interval, and then
finally once the last point has been sent.
Ben Johnson
Jonathan A. Sternberg
Edd Robinson