{"html_url": "https://github.com/simonw/datasette/issues/1231#issuecomment-781560989", "issue_url": "https://api.github.com/repos/simonw/datasette/issues/1231", "id": 781560989, "node_id": "MDEyOklzc3VlQ29tbWVudDc4MTU2MDk4OQ==", "user": {"value": 9599, "label": "simonw"}, "created_at": "2021-02-18T18:50:53Z", "updated_at": "2021-02-18T18:50:53Z", "author_association": "OWNER", "body": "Ideally I'd figure out a way to replicate this error in a concurrent unit test.", "reactions": "{\"total_count\": 0, \"+1\": 0, \"-1\": 0, \"laugh\": 0, \"hooray\": 0, \"confused\": 0, \"heart\": 0, \"rocket\": 0, \"eyes\": 0}", "issue": {"value": 811367257, "label": "Race condition errors in new refresh_schemas() mechanism"}, "performed_via_github_app": null}
{"html_url": "https://github.com/simonw/datasette/issues/1231#issuecomment-781560865", "issue_url": "https://api.github.com/repos/simonw/datasette/issues/1231", "id": 781560865, "node_id": "MDEyOklzc3VlQ29tbWVudDc4MTU2MDg2NQ==", "user": {"value": 9599, "label": "simonw"}, "created_at": "2021-02-18T18:50:38Z", "updated_at": "2021-02-18T18:50:38Z", "author_association": "OWNER", "body": "I started trying to use locks to resolve this but I've not figured out the right way to do that yet - here's my first experiment:\r\n```diff\r\ndiff --git a/datasette/app.py b/datasette/app.py\r\nindex 9e15a16..1681c9d 100644\r\n--- a/datasette/app.py\r\n+++ b/datasette/app.py\r\n@@ -217,6 +217,7 @@ class Datasette:\r\n         self.inspect_data = inspect_data\r\n         self.immutables = set(immutables or [])\r\n         self.databases = collections.OrderedDict()\r\n+        self._refresh_schemas_lock = threading.Lock()\r\n         if memory or not self.files:\r\n             self.add_database(Database(self, is_memory=True), name=\"_memory\")\r\n         # memory_name is a random string so that each Datasette instance gets its own\r\n@@ -324,6 +325,13 @@ class Datasette:\r\n         self.client = DatasetteClient(self)\r\n \r\n     async def refresh_schemas(self):\r\n+        return\r\n+        if self._refresh_schemas_lock.locked():\r\n+            return\r\n+        with self._refresh_schemas_lock:\r\n+            await self._refresh_schemas()\r\n+\r\n+    async def _refresh_schemas(self):\r\n         internal_db = self.databases[\"_internal\"]\r\n         if not self.internal_db_created:\r\n             await init_internal_db(internal_db)\r\n```", "reactions": "{\"total_count\": 0, \"+1\": 0, \"-1\": 0, \"laugh\": 0, \"hooray\": 0, \"confused\": 0, \"heart\": 0, \"rocket\": 0, \"eyes\": 0}", "issue": {"value": 811367257, "label": "Race condition errors in new refresh_schemas() mechanism"}, "performed_via_github_app": null}