Graduate native histogram ingestion and close the v1-guarantees gaps

-blocks-storage.tsdb.enable-native-histograms shipped as experimental in 1.18.0, so
1.22.0 is four minors and roughly two years of exposure later. docs/guides/native-histograms.md
already carries no experimental language, which contradicted v1-guarantees.md. Graduate the
ingestion flag; the flag name does not change, so no deprecation shim is needed. This does not
touch -blocks-storage.tsdb.out-of-order-cap-max, which has its own bullet.

Also record the experimental flags this cycle added without a v1-guarantees entry:

- -distributor.num-query-workers (#7623), marked EXPERIMENTAL in its flag help.
- The whole Thanos PromQL engine surface. -querier.thanos-engine says "Experimental." in its
  help but nothing from pkg/engine/config.go was listed.
- The whole parquet flag surface; only -parquet-converter.max-num-columns was listed. Grouped
  by prefix rather than enumerated, since the cache flags are boilerplate.
- -querier.query-protection.rejection (#7442) and
  -querier.query-protection.eviction.max-evictions-per-cycle (#7488).

Parquet and the tenant-federation regex matcher are deliberately not graduated: the parquet
proposal is still "Status: Proposed", docs/guides/parquet-mode.md still warns it is experimental,
and #7610 changed the file format this cycle. The regex matcher has only two minors of exposure
and #7562 fixed cross-tenant stale cache reads this cycle.

Refs #5922

Signed-off-by: Charlie Le <charlie_le@apple.com>

Author: CharlieTLe

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## master / unreleased
 * [FEATURE] Engine: Add `-querier.selector-batch-size` and `-ruler.selector-batch-size` flags to configure series batching in the Thanos promQL engine. 0 disables batching. #7763
+* [CHANGE] Ingester: Graduate native histogram ingestion (`-blocks-storage.tsdb.enable-native-histograms`) from experimental. #7789
 * [CHANGE] Querier: Make query time range configurations per-tenant: `query_ingesters_within`, `query_store_after`, and `shuffle_sharding_ingesters_lookback_period`. Uses `model.Duration` instead of `time.Duration` to support serialization but has minimum unit of 1ms (nanoseconds/microseconds not supported). #7160
 * [CHANGE] Cache: Setting `-blocks-storage.bucket-store.metadata-cache.bucket-index-content-ttl` to 0 will disable the bucket-index cache. #7446
 * [CHANGE] HA Tracker: Move `-distributor.ha-tracker.failover-timeout` from a global config to a per-tenant runtime config. The flag name and default value (30s) remain the same. #7481

docs/configuration/v1-guarantees.md

@@ -52,6 +52,7 @@ Currently experimental features are:
   - Do not extend writes on unhealthy ingesters (`-distributor.extend-writes=false`)
   - Accept multiple HA pairs in the same request (enabled via `-experimental.distributor.ha-tracker.mixed-ha-samples=true`)
   - Accept Prometheus remote write 2.0 request (`-distributor.remote-writev2-enabled=true`)
+  - Use a goroutine worker pool for query fan-out calls to ingesters (`-distributor.num-query-workers`)
 - Tenant Deletion in Purger, for blocks storage.
 - Blocks storage user index
 - Store Gateway max concurrent fetched data bytes limit
@@ -103,8 +104,6 @@ Currently experimental features are:
   - Ingest delta temporality OTLP metrics (`-distributor.otlp.allow-delta-temporality=true`)
 - Persistent tokens in the Ruler Ring:
   - `-ruler.ring.tokens-file-path` (path) CLI flag
-- Native Histograms
-  - Ingestion can be enabled by setting `-blocks-storage.tsdb.enable-native-histograms=true` on Ingester.
 - String interning for metrics labels
   - Enable string interning for metrics labels by setting `-ingester.labels-string-interning-enabled` on Ingester.
 - Query-frontend: query rejection (`-frontend.query-rejection.enabled`)
@@ -113,9 +112,10 @@ Currently experimental features are:
 - Query-frontend: dynamic query splits
   - `querier.max-shards-per-query` (int) CLI flag
   - `querier.max-fetched-data-duration-per-query` (duration) CLI flag
-- Ingester/Store-Gateway: Query rejection
+- Ingester/Store-Gateway/Querier: Query rejection
   - `-ingester.query-protection.rejection`
   - `-store-gateway.query-protection.rejection`
+  - `-querier.query-protection.rejection`
 - Distributor/Ingester: Stream push connection
   - Enable stream push connection between distributor and ingester by setting `-distributor.use-stream-push=true` on Distributor.
   - Enable stream push authentication on Distributor/Ingester. (`-distributor.sign-write-requests-keys`)
@@ -141,6 +141,7 @@ Currently experimental features are:
   - `-querier.query-protection.eviction.cooldown-period` (int)
   - `-querier.query-protection.eviction.eviction-metric` (string)
   - `-querier.query-protection.eviction.min-query-age` (duration)
+  - `-querier.query-protection.eviction.max-evictions-per-cycle` (int)
 - Ingester: Active Series Tracker
   - Per-tenant `active_series_trackers` configuration in runtime config overrides
   - Counts active series matching PromQL label matchers and exposes `cortex_ingester_active_series_per_tracker` metric
@@ -154,6 +155,19 @@ Currently experimental features are:
   - `-ingester.head-queried-series-metrics-windows` time windows to report (default: 2h)
   - `-ingester.head-queried-series-metrics-window-duration` HLL sub-window size
   - `-ingester.head-queried-series-metrics-sample-rate` query sampling rate
-- Parquet Converter: Maximum number of columns per file
-  - `-parquet-converter.max-num-columns` (int) CLI flag
-  - Automatically shards parquet files when the number of columns exceeds the configured limit
+- Parquet storage
+  - Parquet Converter: the `-parquet-converter.*` CLI flags, including `-parquet-converter.enabled`,
+    `-parquet-converter.max-num-columns` (automatically shards parquet files when the number of columns
+    exceeds the configured limit) and the `-parquet-converter.ring.*` ring configuration
+  - Querier: `-querier.parquet-queryable-default-block-store`, `-querier.parquet-queryable-fallback-disabled`,
+    the `-querier.parquet-queryable.max-fetched-*` limits and `-querier.parquet-shard-cache-*`
+  - Store Gateway: `-blocks-storage.bucket-store.parquet-query-concurrency`,
+    `-blocks-storage.bucket-store.parquet-shard-cache-*` and the
+    `-blocks-storage.bucket-store.parquet-labels-cache.*` /
+    `-blocks-storage.bucket-store.parquet-row-ranges-cache.*` cache configuration
+- Querier/Ruler: Thanos PromQL engine
+  - `-querier.thanos-engine` / `-ruler.thanos-engine` (boolean) CLI flags
+  - `-querier.enable-x-functions` / `-ruler.enable-x-functions` (boolean) CLI flags
+  - `-querier.optimizers` / `-ruler.optimizers` (string) CLI flags
+  - `-querier.decoding-concurrency` / `-ruler.decoding-concurrency` (int) CLI flags
+  - `-querier.selector-batch-size` / `-ruler.selector-batch-size` (int) CLI flags