feat(discover): allow querying for cache.item_size and cache.hit

src/sentry/search/events/builder/metrics.py

@@ -353,10 +353,11 @@ def is_performance(self) -> bool:
 
     @property
     def use_case_id(self) -> UseCaseID:
-        if self.is_performance:
-            return UseCaseID.TRANSACTIONS
-        elif self.spans_metrics_builder:
+
+        if self.spans_metrics_builder:
             return UseCaseID.SPANS
+        elif self.is_performance:
+            return UseCaseID.TRANSACTIONS
         else:
             return UseCaseID.SESSIONS
 

src/sentry/search/events/constants.py

@@ -311,6 +311,7 @@ class ThresholdDict(TypedDict):
     "query_hash",
     "release",
     "resource.render_blocking_status",
+    "cache.hit",
     "satisfaction",
     "sdk",
     "session.status",
@@ -327,6 +328,7 @@ class ThresholdDict(TypedDict):
     "http.response_content_length": "d:spans/http.response_content_length@byte",
     "http.decoded_response_content_length": "d:spans/http.decoded_response_content_length@byte",
     "http.response_transfer_size": "d:spans/http.response_transfer_size@byte",
+    "cache.item_size": "d:spans/cache.item_size@byte",
 }
 SELF_TIME_LIGHT = "d:spans/exclusive_time_light@millisecond"
 # 50 to match the size of tables in the UI + 1 for pagination reasons

src/sentry/snuba/metrics/naming_layer/mri.py

@@ -168,6 +168,7 @@ class SpanMRI(Enum):
     SELF_TIME_LIGHT = "d:spans/exclusive_time_light@millisecond"
     RESPONSE_CONTENT_LENGTH = "d:spans/http.response_content_length@byte"
     DECODED_RESPONSE_CONTENT_LENGTH = "d:spans/http.decoded_response_content_length@byte"
+    CACHE_ITEM_SIZE = "d:spans/cache.item_size@byte"
     RESPONSE_TRANSFER_SIZE = "d:spans/http.response_transfer_size@byte"
 
     # Derived

src/sentry/snuba/metrics/naming_layer/public.py

@@ -120,6 +120,7 @@ class SpanMetricKey(Enum):
     RESPONSE_CONTENT_LENGTH = "http.response_content_length"
     DECODED_RESPONSE_CONTENT_LENGTH = "http.decoded_response_content_length"
     RESPONSE_TRANSFER_SIZE = "http.response_transfer_size"
+    CACHE_ITEM_SIZE = "cache.item_size"
 
     HTTP_ERROR_COUNT = "span.http_error_count"
     HTTP_ERROR_RATE = "span.http_error_rate"

src/sentry/testutils/cases.py

@@ -2019,6 +2019,7 @@ class MetricsEnhancedPerformanceTestCase(BaseMetricsLayerTestCase, TestCase):
         "span.self_time": "metrics_distributions",
         "http.response_content_length": "metrics_distributions",
         "http.decoded_response_content_length": "metrics_distributions",
+        "cache.item_size": "metrics_distributions",
         "http.response_transfer_size": "metrics_distributions",
         "measurements.lcp": "metrics_distributions",
         "measurements.fp": "metrics_distributions",

tests/sentry/snuba/metrics/fields/test_base.py

@@ -71,6 +71,7 @@ def get_entity_of_metric_mocked(_, metric_mri, use_case_id):
         SpanMRI.RESPONSE_CONTENT_LENGTH.value: EntityKey.MetricsDistributions,
         SpanMRI.DECODED_RESPONSE_CONTENT_LENGTH.value: EntityKey.MetricsDistributions,
         SpanMRI.RESPONSE_TRANSFER_SIZE.value: EntityKey.MetricsDistributions,
+        SpanMRI.CACHE_ITEM_SIZE.value: EntityKey.MetricsDistributions,
     }[metric_mri]
 
 

tests/snuba/api/endpoints/test_organization_events_stats_span_metrics.py

@@ -270,6 +270,34 @@ def test_resource_transfer_size(self):
         assert not data[0][1][0]["count"]
         assert data[1][1][0]["count"] == 4.0
 
+    def test_cache_item_size(self):
+        self.store_span_metric(
+            4,
+            metric="cache.item_size",
+            timestamp=self.day_ago + timedelta(minutes=1),
+            tags={"transaction": "foo", "cache.hit": "true"},
+        )
+
+        response = self.do_request(
+            data={
+                "start": iso_format(self.day_ago),
+                "end": iso_format(self.day_ago + timedelta(minutes=2)),
+                "interval": "1m",
+                "yAxis": "avg(cache.item_size)",
+                "field": ["cache.hit"],
+                "project": self.project.id,
+                "dataset": "spansMetrics",
+                "excludeOther": 0,
+            },
+        )
+
+        assert response.status_code == 200
+
+        data = response.data["data"]
+        assert len(data) == 2
+        assert not data[0][1][0]["count"]
+        assert data[1][1][0]["count"] == 4.0
+
 
 class OrganizationEventsStatsSpansMetricsEndpointTestWithMetricLayer(
     OrganizationEventsStatsSpansMetricsEndpointTest