Add counter for chunks from ingesters entirely deduplicated

[56quarters]

What this PR does

Add a counter for tracking the number of chunks that could be entirely discarded
as duplicates of an existing chunk when querying ingesters. This is a requirement
of testing distributor <-> ingester timeout changes.

Signed-off-by: Nick Pillitteri nick.pillitteri@grafana.com

Which issue(s) this PR fixes or relates to

N/A

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[pstibrany]

Change looks good to me. It would be nice to have a unit test for this change too.

[56quarters]

Change looks good to me. It would be nice to have a unit test for this change too.

I'm struggling to come up with a good way to test this without a lot of refactoring. Because this runs as an operation against the ring, it seems that the operation returns as soon as the required number of ingesters have responded. I've tried with 3 ingesters and RF=3 as well as 2 ingesters and RF=2.

[pstibrany]

I'm struggling to come up with a good way to test this without a lot of refactoring. Because this runs as an operation against the ring, it seems that the operation returns as soon as the required number of ingesters have responded. I've tried with 3 ingesters and RF=3 as well as 2 ingesters and RF=2.

Perhaps adding a check into some integration test would be much simpler -- just see if the metric has expected value. But feel free to not block on the test.