feat(discover): add cache_miss_rate function to discover (#69617)

Adds the cache_miss_rate function to discover

Author: DominikB2014

src/sentry/search/events/datasets/spans_metrics.py

@@ -388,6 +388,15 @@ def function_converter(self) -> Mapping[str, fields.MetricsFunction]:
                     ),
                     default_result_type="percentage",
                 ),
+                fields.MetricsFunction(
+                    "cache_miss_rate",
+                    snql_distribution=lambda args, alias: function_aliases.resolve_division(
+                        self._resolve_cache_miss_count(args),
+                        self._resolve_cache_hit_and_miss_count(args),
+                        alias,
+                    ),
+                    default_result_type="percentage",
+                ),
                 # TODO: Deprecated, use `http_response_rate(5)` instead
                 fields.MetricsFunction(
                     "http_error_rate",
@@ -741,6 +750,30 @@ def _resolve_cache_hit_count(
             alias,
         )
 
+    def _resolve_cache_miss_count(
+        self,
+        _: Mapping[str, str | Column | SelectType | int | float],
+        alias: str | None = None,
+    ) -> SelectType:
+
+        return self._resolve_count_if(
+            Function(
+                "equals",
+                [
+                    Column("metric_id"),
+                    self.resolve_metric("span.self_time"),
+                ],
+            ),
+            Function(
+                "equals",
+                [
+                    self.builder.column("cache.hit"),
+                    self.builder.resolve_tag_value("false"),
+                ],
+            ),
+            alias,
+        )
+
     def _resolve_cache_hit_and_miss_count(
         self,
         _: Mapping[str, str | Column | SelectType | int | float],

tests/snuba/api/endpoints/test_organization_events_span_metrics.py

@@ -1060,6 +1060,47 @@ def test_cache_hit_rate(self):
         assert meta["dataset"] == "spansMetrics"
         assert meta["fields"]["cache_hit_rate()"] == "percentage"
 
+    def test_cache_miss_rate(self):
+        self.store_span_metric(
+            1,
+            internal_metric=constants.SELF_TIME_LIGHT,
+            timestamp=self.min_ago,
+            tags={"cache.hit": "true"},
+        )
+        self.store_span_metric(
+            1,
+            internal_metric=constants.SELF_TIME_LIGHT,
+            timestamp=self.min_ago,
+            tags={"cache.hit": "false"},
+        )
+        self.store_span_metric(
+            1,
+            internal_metric=constants.SELF_TIME_LIGHT,
+            timestamp=self.min_ago,
+            tags={"cache.hit": "false"},
+        )
+        self.store_span_metric(
+            1,
+            internal_metric=constants.SELF_TIME_LIGHT,
+            timestamp=self.min_ago,
+            tags={"cache.hit": "false"},
+        )
+        response = self.do_request(
+            {
+                "field": ["cache_miss_rate()"],
+                "query": "",
+                "project": self.project.id,
+                "dataset": "spansMetrics",
+            }
+        )
+        assert response.status_code == 200, response.content
+        data = response.data["data"]
+        meta = response.data["meta"]
+        assert len(data) == 1
+        assert data[0]["cache_miss_rate()"] == 0.75
+        assert meta["dataset"] == "spansMetrics"
+        assert meta["fields"]["cache_miss_rate()"] == "percentage"
+
     def test_http_response_rate(self):
         self.store_span_metric(
             1,