Add RW2 support (#11100)

* Add unmarshal benchmark
* feat(rw2): unmarshal RW1 request from RW2

Implement unmarshal of Prometheus remote write request 1.0 data
from Remote Write 2.0 input by converting the model.

The conversion is lossy as RW1 does not have metadata per series, only
per metric family.

* test(rw2): enhance distributor integration tests

Duplicate all existing testcases with RW2.
Add metadata check.

Signed-off-by: György Krajcsovits <[email protected]>
Signed-off-by: Arve Knudsen <[email protected]>

Author: krajorama

CHANGELOG.md

@@ -9,6 +9,7 @@
 * [CHANGE] Distributor: removed the `cortex_distributor_label_values_with_newlines_total` metric. #10977
 * [CHANGE] Ingester/Distributor: renamed the experimental `max_cost_attribution_cardinality_per_user` config to `max_cost_attribution_cardinality`. #11092
 * [CHANGE] Frontend: The subquery spin-off feature is now enabled with `-query-frontend.subquery-spin-off-enabled=true` instead of `-query-frontend.instant-queries-with-subquery-spin-off=.*` #11153
+* [FEATURE] Distributor: experimental support for Prometheus Remote Write 2.0 protocol. Limitations: created timestamp is ignored, native histograms with custom buckets are rejected, per series metadata is merged on metric family level automatically, ingestion might fail if client sends ProtoBuf fields out of order. #11100 #11101
 * [ENHANCEMENT] Ingester: Add support for exporting native histogram cost attribution metrics (`cortex_ingester_attributed_active_native_histogram_series` and `cortex_ingester_attributed_active_native_histogram_buckets`) with labels specified by customers to a custom Prometheus registry. #10892
 * [ENHANCEMENT] Store-gateway: Download sparse headers uploaded by compactors. Compactors have to be configured with `-compactor.upload-sparse-index-headers=true` option. #10879 #11072.
 * [ENHANCEMENT] Compactor: Upload block index file and multiple segment files concurrently. Concurrency scales linearly with block size up to `-compactor.max-per-block-upload-concurrency`. #10947