Merge pull request #3897 from ClickHouse/Blargian-patch-31

[Feedback] ClickStack: correct exponential histogram schema

Author: Blargian

docs/use-cases/observability/clickstack/ingesting-data/schemas.md

@@ -208,14 +208,16 @@ CREATE TABLE otel_metrics_histogram
 ENGINE = SharedMergeTree('/clickhouse/tables/{uuid}/{shard}', '{replica}')
 PARTITION BY toDate(TimeUnix)
 ORDER BY (ServiceName, MetricName, Attributes, toUnixTimestamp64Nano(TimeUnix))
-SETTINGS index_granularity = 8192"
 ```
 
 ### Exponential histograms {#exponential-histograms}
 
+:::note
+HyperDX does not support fetching/displaying exponential histogram metrics yet. Users may configure them in the metrics source but future support is forthcoming.
+:::
+
 ```sql
-CREATE TABLE otel_metrics_histogram
-(
+CREATE TABLE otel_metrics_exponentialhistogram (
     `ResourceAttributes` Map(LowCardinality(String), String) CODEC(ZSTD(1)),
     `ResourceSchemaUrl` String CODEC(ZSTD(1)),
     `ScopeName` String CODEC(ZSTD(1)),
@@ -228,18 +230,24 @@ CREATE TABLE otel_metrics_histogram
     `MetricDescription` String CODEC(ZSTD(1)),
     `MetricUnit` String CODEC(ZSTD(1)),
     `Attributes` Map(LowCardinality(String), String) CODEC(ZSTD(1)),
-    `StartTimeUnix` DateTime64(9) CODEC(Delta(8), ZSTD(1)),
-    `TimeUnix` DateTime64(9) CODEC(Delta(8), ZSTD(1)),
-    `Count` UInt64 CODEC(Delta(8), ZSTD(1)),
-    `Sum` Float64 CODEC(ZSTD(1)),
-    `BucketCounts` Array(UInt64) CODEC(ZSTD(1)),
-    `ExplicitBounds` Array(Float64) CODEC(ZSTD(1)),
-    `Exemplars.FilteredAttributes` Array(Map(LowCardinality(String), String)) CODEC(ZSTD(1)),
-    `Exemplars.TimeUnix` Array(DateTime64(9)) CODEC(ZSTD(1)),
-    `Exemplars.Value` Array(Float64) CODEC(ZSTD(1)),
-    `Exemplars.SpanId` Array(String) CODEC(ZSTD(1)),
-    `Exemplars.TraceId` Array(String) CODEC(ZSTD(1)),
-    `Flags` UInt32 CODEC(ZSTD(1)),
+    `StartTimeUnix` DateTime64(9) CODEC(Delta, ZSTD(1)),
+    `TimeUnix` DateTime64(9) CODEC(Delta, ZSTD(1)),
+    `Count UInt64` CODEC(Delta, ZSTD(1)),
+    `Sum Float64` CODEC(ZSTD(1)),
+    `Scale Int32` CODEC(ZSTD(1)),
+    `ZeroCount` UInt64 CODEC(ZSTD(1)),
+    `PositiveOffset` Int32 CODEC(ZSTD(1)),
+    `PositiveBucketCounts` Array(UInt64) CODEC(ZSTD(1)),
+    `NegativeOffset` Int32 CODEC(ZSTD(1)),
+    `NegativeBucketCounts` Array(UInt64) CODEC(ZSTD(1)),
+    `Exemplars` Nested (
+        FilteredAttributes Map(LowCardinality(String), String),
+        TimeUnix DateTime64(9),
+        Value Float64,
+        SpanId String,
+        TraceId String
+    ) CODEC(ZSTD(1)),
+    `Flags` UInt32  CODEC(ZSTD(1)),
     `Min` Float64 CODEC(ZSTD(1)),
     `Max` Float64 CODEC(ZSTD(1)),
     `AggregationTemporality` Int32 CODEC(ZSTD(1)),