chore: [SVLS-5973] fewer count buckets

ddtrace/_trace/telemetry.py

@@ -14,9 +14,19 @@ def record_span_pointer_calculation(context: str, span_pointer_count: int) -> No
 
 
 def _span_pointer_count_to_tag(span_pointer_count: int) -> str:
-    if span_pointer_count <= 20:
+    if span_pointer_count < 0:
+        # this shouldn't be possible, but let's make sure
+        return "negative"
+
+    elif span_pointer_count <= 5:
         return str(span_pointer_count)
 
+    elif span_pointer_count <= 10:
+        return "6-10"
+
+    elif span_pointer_count <= 20:
+        return "11-20"
+
     elif span_pointer_count <= 50:
         return "21-50"
 

tests/tracer/test_telemetry.py

@@ -6,12 +6,19 @@
 
 
 def test_span_pointer_count_to_tag_returns_strings() -> None:
-    for count in range(0, 500):
+    unique_tags = set()
+
+    for count in range(-10, 500):
         tag = _span_pointer_count_to_tag(count)
 
         assert isinstance(tag, str)
         assert tag != ""
 
+        unique_tags.add(tag)
+
+    reasonable_cadinality_limit = 15
+    assert len(unique_tags) <= reasonable_cadinality_limit
+
 
 class SpanPointerTagCase(NamedTuple):
     count: int
@@ -21,6 +28,10 @@ class SpanPointerTagCase(NamedTuple):
 @pytest.mark.parametrize(
     "test_case",
     [
+        SpanPointerTagCase(
+            count=-1,
+            expected="negative",
+        ),
         SpanPointerTagCase(
             count=0,
             expected="0",
@@ -35,7 +46,7 @@ class SpanPointerTagCase(NamedTuple):
         ),
         SpanPointerTagCase(
             count=15,
-            expected="15",
+            expected="11-20",
         ),
         SpanPointerTagCase(
             count=25,