chore: make deletion batch size configurable via setting

docs/v3/develop/settings-ref.mdx

@@ -1580,6 +1580,18 @@ The maximum number of seconds between flushes of the event persister.
 **Supported environment variables**:
 `PREFECT_SERVER_SERVICES_EVENT_PERSISTER_FLUSH_INTERVAL`, `PREFECT_API_SERVICES_EVENT_PERSISTER_FLUSH_INTERVAL`
 
+### `batch_size_delete`
+The number of expired events and event resources the event persister will attempt to delete in one batch.
+
+**Type**: `integer`
+
+**Default**: `10000`
+
+**TOML dotted key path**: `server.services.event_persister.batch_size_delete`
+
+**Supported environment variables**:
+`PREFECT_SERVER_SERVICES_EVENT_PERSISTER_BATCH_SIZE_DELETE`
+
 ---
 ## ServerServicesFlowRunNotificationsSettings
 Settings for controlling the flow run notifications service

schemas/settings.schema.json

@@ -1416,6 +1416,16 @@
                     ],
                     "title": "Flush Interval",
                     "type": "number"
+                },
+                "batch_size_delete": {
+                    "default": 10000,
+                    "description": "The number of expired events and event resources the event persister will attempt to delete in one batch.",
+                    "exclusiveMinimum": 0,
+                    "supported_environment_variables": [
+                        "PREFECT_SERVER_SERVICES_EVENT_PERSISTER_BATCH_SIZE_DELETE"
+                    ],
+                    "title": "Batch Size Delete",
+                    "type": "integer"
                 }
             },
             "title": "ServerServicesEventPersisterSettings",

src/prefect/server/events/services/event_persister.py

@@ -28,6 +28,7 @@
     PREFECT_API_SERVICES_EVENT_PERSISTER_BATCH_SIZE,
     PREFECT_API_SERVICES_EVENT_PERSISTER_FLUSH_INTERVAL,
     PREFECT_EVENTS_RETENTION_PERIOD,
+    PREFECT_SERVER_SERVICES_EVENT_PERSISTER_BATCH_SIZE_DELETE,
 )
 from prefect.settings.context import get_current_settings
 from prefect.settings.models.server.services import ServicesBaseSetting
@@ -167,18 +168,23 @@ async def flush() -> None:
 
     async def trim() -> None:
         older_than = DateTime.now("UTC") - PREFECT_EVENTS_RETENTION_PERIOD.value()
-
+        delete_batch_size = (
+            PREFECT_SERVER_SERVICES_EVENT_PERSISTER_BATCH_SIZE_DELETE.value()
+        )
         try:
             async with db.session_context() as session:
                 resource_count = await batch_delete(
                     session,
                     db.EventResource,
                     db.EventResource.updated < older_than,
-                    batch_size=10_000,
+                    batch_size=delete_batch_size,
                 )
 
                 event_count = await batch_delete(
-                    session, db.Event, db.Event.occurred < older_than, batch_size=10_000
+                    session,
+                    db.Event,
+                    db.Event.occurred < older_than,
+                    batch_size=delete_batch_size,
                 )
 
                 if resource_count or event_count:

src/prefect/settings/models/server/services.py

@@ -85,6 +85,16 @@ class ServerServicesEventPersisterSettings(ServicesBaseSetting):
         ),
     )
 
+    batch_size_delete: int = Field(
+        default=10_000,
+        gt=0,
+        description="The number of expired events and event resources the event persister will attempt to delete in one batch.",
+        validation_alias=AliasChoices(
+            AliasPath("batch_size_delete"),
+            "prefect_server_services_event_persister_batch_size_delete",
+        ),
+    )
+
 
 class ServerServicesEventLoggerSettings(ServicesBaseSetting):
     """

tests/test_settings.py

@@ -362,6 +362,7 @@
     "PREFECT_SERVER_SERVICES_CANCELLATION_CLEANUP_LOOP_SECONDS": {"test_value": 10.0},
     "PREFECT_SERVER_SERVICES_EVENT_LOGGER_ENABLED": {"test_value": True},
     "PREFECT_SERVER_SERVICES_EVENT_PERSISTER_BATCH_SIZE": {"test_value": 10},
+    "PREFECT_SERVER_SERVICES_EVENT_PERSISTER_BATCH_SIZE_DELETE": {"test_value": 20},
     "PREFECT_SERVER_SERVICES_EVENT_PERSISTER_ENABLED": {"test_value": True},
     "PREFECT_SERVER_SERVICES_EVENT_PERSISTER_FLUSH_INTERVAL": {"test_value": 10.0},
     "PREFECT_SERVER_SERVICES_FLOW_RUN_NOTIFICATIONS_ENABLED": {"test_value": True},