Revert "POC delete stale non-e2e devices for users (#14038)" (#14582)

Author: David Robertson

changelog.d/14582.bugfix

@@ -0,0 +1 @@
+Fix a regression in Synapse 1.73.0rc1 where Synapse's main process would stop responding to HTTP requests when a user with a large number of devices logs in.

synapse/handlers/device.py

@@ -421,9 +421,6 @@ async def check_device_registered(
 
         self._check_device_name_length(initial_device_display_name)
 
-        # Prune the user's device list if they already have a lot of devices.
-        await self._prune_too_many_devices(user_id)
-
         if device_id is not None:
             new_device = await self.store.store_device(
                 user_id=user_id,
@@ -455,14 +452,6 @@ async def check_device_registered(
 
         raise errors.StoreError(500, "Couldn't generate a device ID.")
 
-    async def _prune_too_many_devices(self, user_id: str) -> None:
-        """Delete any excess old devices this user may have."""
-        device_ids = await self.store.check_too_many_devices_for_user(user_id)
-        if not device_ids:
-            return
-
-        await self.delete_devices(user_id, device_ids)
-
     async def _delete_stale_devices(self) -> None:
         """Background task that deletes devices which haven't been accessed for more than
         a configured time period.
@@ -492,7 +481,7 @@ async def delete_all_devices_for_user(
             device_ids = [d for d in device_ids if d != except_device_id]
         await self.delete_devices(user_id, device_ids)
 
-    async def delete_devices(self, user_id: str, device_ids: Collection[str]) -> None:
+    async def delete_devices(self, user_id: str, device_ids: List[str]) -> None:
         """Delete several devices
 
         Args:

synapse/storage/databases/main/devices.py

@@ -1533,71 +1533,6 @@ def _txn(txn: LoggingTransaction) -> int:
 
         return rows
 
-    async def check_too_many_devices_for_user(self, user_id: str) -> Collection[str]:
-        """Check if the user has a lot of devices, and if so return the set of
-        devices we can prune.
-
-        This does *not* return hidden devices or devices with E2E keys.
-        """
-
-        num_devices = await self.db_pool.simple_select_one_onecol(
-            table="devices",
-            keyvalues={"user_id": user_id, "hidden": False},
-            retcol="COALESCE(COUNT(*), 0)",
-            desc="count_devices",
-        )
-
-        # We let users have up to ten devices without pruning.
-        if num_devices <= 10:
-            return ()
-
-        # We prune everything older than N days.
-        max_last_seen = self._clock.time_msec() - 14 * 24 * 60 * 60 * 1000
-
-        if num_devices > 50:
-            # If the user has more than 50 devices, then we chose a last seen
-            # that ensures we keep at most 50 devices.
-            sql = """
-                SELECT last_seen FROM devices
-                LEFT JOIN e2e_device_keys_json USING (user_id, device_id)
-                WHERE
-                    user_id = ?
-                    AND NOT hidden
-                    AND last_seen IS NOT NULL
-                    AND key_json IS NULL
-                ORDER BY last_seen DESC
-                LIMIT 1
-                OFFSET 50
-            """
-
-            rows = await self.db_pool.execute(
-                "check_too_many_devices_for_user_last_seen", None, sql, (user_id,)
-            )
-            if rows:
-                max_last_seen = max(rows[0][0], max_last_seen)
-
-        # Now fetch the devices to delete.
-        sql = """
-            SELECT DISTINCT device_id FROM devices
-            LEFT JOIN e2e_device_keys_json USING (user_id, device_id)
-            WHERE
-                user_id = ?
-                AND NOT hidden
-                AND last_seen < ?
-                AND key_json IS NULL
-        """
-
-        def check_too_many_devices_for_user_txn(
-            txn: LoggingTransaction,
-        ) -> Collection[str]:
-            txn.execute(sql, (user_id, max_last_seen))
-            return {device_id for device_id, in txn}
-
-        return await self.db_pool.runInteraction(
-            "check_too_many_devices_for_user",
-            check_too_many_devices_for_user_txn,
-        )
-
 
 class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
     # Because we have write access, this will be a StreamIdGenerator
@@ -1656,7 +1591,6 @@ async def store_device(
                 values={},
                 insertion_values={
                     "display_name": initial_device_display_name,
-                    "last_seen": self._clock.time_msec(),
                     "hidden": False,
                 },
                 desc="store_device",
@@ -1702,7 +1636,7 @@ async def store_device(
             )
             raise StoreError(500, "Problem storing device.")
 
-    async def delete_devices(self, user_id: str, device_ids: Collection[str]) -> None:
+    async def delete_devices(self, user_id: str, device_ids: List[str]) -> None:
         """Deletes several devices.
 
         Args:

tests/handlers/test_device.py

@@ -115,7 +115,7 @@ def test_get_devices_by_user(self) -> None:
                 "device_id": "xyz",
                 "display_name": "display 0",
                 "last_seen_ip": None,
-                "last_seen_ts": 1000000,
+                "last_seen_ts": None,
             },
             device_map["xyz"],
         )

tests/storage/test_client_ips.py

@@ -169,8 +169,6 @@ def test_get_last_client_ip_by_device(self, after_persisting: bool):
             )
         )
 
-        last_seen = self.clock.time_msec()
-
         if after_persisting:
             # Trigger the storage loop
             self.reactor.advance(10)
@@ -191,7 +189,7 @@ def test_get_last_client_ip_by_device(self, after_persisting: bool):
                         "device_id": device_id,
                         "ip": None,
                         "user_agent": None,
-                        "last_seen": last_seen,
+                        "last_seen": None,
                     },
                 ],
             )