SQLServer: Add lookback_window param. (#18979)

* Ad lookback_window param.

* Changelog.

* Run linter.

* Add config param to spec.

* Match config spec.

* Fix type.

* Sync models.

* Remove default value, since there is none.

* Change default value.

* Add example val.

sqlserver/assets/configuration/spec.yaml

@@ -411,6 +411,15 @@ files:
             example: 250
             display_default: 250
           hidden: true
+        - name: lookback_window
+          description: |
+            Queries whose last execution completed after the lookback window are excluded from
+            metrics collection. Set a longer lookback window (in seconds) to capture infrequently
+            run queries.
+          value:
+            type: integer
+            display_default: 2 * collection_interval
+            example: 600
     - name: procedure_metrics
       description: Configure collection of procedure metrics
       options:

sqlserver/changelog.d/18979.added

@@ -0,0 +1,7 @@
+Add lookback_window config parameter to query_metrics.
+
+The current lookback window defaults to 2 times the collection interval, and is not able to be overridden.
+This means that infrequently-run queries are unlikely to have metrics captured for them. One common
+use case that falls into this bucket is ETL queries which can run hourly or even daily. These have
+a very small chance of having metrics captured for them. In that case, we will support setting a lookback
+window that will include such queries.

sqlserver/datadog_checks/sqlserver/config_models/instance.py

@@ -155,6 +155,7 @@ class QueryMetrics(BaseModel):
     dm_exec_query_stats_row_limit: Optional[int] = None
     enabled: Optional[bool] = None
     enforce_collection_interval_deadline: Optional[bool] = None
+    lookback_window: Optional[int] = None
     max_queries: Optional[int] = None
     samples_per_hour_per_query: Optional[int] = None
 

sqlserver/datadog_checks/sqlserver/data/conf.yaml.example

@@ -354,6 +354,13 @@ instances:
         #
         # samples_per_hour_per_query: 4
 
+        ## @param lookback_window - integer - optional - default: 2 * collection_interval
+        ## Queries whose last execution completed after the lookback window are excluded from
+        ## metrics collection. Set a longer lookback window (in seconds) to capture infrequently
+        ## run queries.
+        #
+        # lookback_window: 600
+
     ## Configure collection of procedure metrics
     #
     # procedure_metrics:

sqlserver/datadog_checks/sqlserver/statements.py

@@ -281,12 +281,17 @@ def _get_statement_metrics_query_cached(self, cursor):
         )
         return self._statement_metrics_query
 
+    def lookback_window(self):
+        return self._config.statement_metrics_config.get('lookback_window', None)
+
     @tracked_method(agent_check_getter=agent_check_getter, track_result_length=True)
     def _load_raw_query_metrics_rows(self, cursor):
         self.log.debug("collecting sql server statement metrics")
         statement_metrics_query = self._get_statement_metrics_query_cached(cursor)
         now = time.time()
         query_interval = self.collection_interval * 2
+        if self.lookback_window():
+            query_interval = self.lookback_window()
         if self._last_stats_query_time:
             query_interval = max(query_interval, now - self._last_stats_query_time)
         self._last_stats_query_time = now

sqlserver/tests/test_statements.py

@@ -1021,6 +1021,16 @@ def test_metrics_lookback_multiplier(instance_docker):
     mock_cursor.execute.assert_called_with(ANY, (6,))
 
 
+@pytest.mark.unit
+def test_metrics_lookback_window_config(instance_docker):
+    instance_docker['query_metrics'] = {'lookback_window': 86400}
+    check = SQLServer(CHECK_NAME, {}, [instance_docker])
+    _, mock_cursor = _mock_database_list()
+
+    check.statement_metrics._load_raw_query_metrics_rows(mock_cursor)
+    mock_cursor.execute.assert_called_with(ANY, (86400,))
+
+
 @pytest.mark.flaky
 @pytest.mark.integration
 @pytest.mark.usefixtures('dd_environment')