Revert #7736 (#8039)

synapse/storage/databases/main/events_worker.py

@@ -41,15 +41,9 @@ from synapse.replication.tcp.streams import BackfillStream
 from synapse.replication.tcp.streams.events import EventsStream
 from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
 from synapse.storage.database import DatabasePool
-from synapse.storage.types import Cursor
 from synapse.storage.util.id_generators import StreamIdGenerator
 from synapse.types import get_domain_from_id
-from synapse.util.caches.descriptors import (
-    Cache,
-    _CacheContext,
-    cached,
-    cachedInlineCallbacks,
-)
+from synapse.util.caches.descriptors import Cache, cached, cachedInlineCallbacks
 from synapse.util.iterutils import batch_iter
 from synapse.util.metrics import Measure
 
@@ -1364,84 +1358,6 @@ class EventsWorkerStore(SQLBaseStore):
             desc="get_next_event_to_expire", func=get_next_event_to_expire_txn
         )
 
-    @cached(tree=True, cache_context=True)
-    async def get_unread_message_count_for_user(
-        self, room_id: str, user_id: str, cache_context: _CacheContext,
-    ) -> int:
-        """Retrieve the count of unread messages for the given room and user.
-
-        Args:
-            room_id: The ID of the room to count unread messages in.
-            user_id: The ID of the user to count unread messages for.
-
-        Returns:
-            The number of unread messages for the given user in the given room.
-        """
-        with Measure(self._clock, "get_unread_message_count_for_user"):
-            last_read_event_id = await self.get_last_receipt_event_id_for_user(
-                user_id=user_id,
-                room_id=room_id,
-                receipt_type="m.read",
-                on_invalidate=cache_context.invalidate,
-            )
-
-            return await self.db_pool.runInteraction(
-                "get_unread_message_count_for_user",
-                self._get_unread_message_count_for_user_txn,
-                user_id,
-                room_id,
-                last_read_event_id,
-            )
-
-    def _get_unread_message_count_for_user_txn(
-        self,
-        txn: Cursor,
-        user_id: str,
-        room_id: str,
-        last_read_event_id: Optional[str],
-    ) -> int:
-        if last_read_event_id:
-            # Get the stream ordering for the last read event.
-            stream_ordering = self.db_pool.simple_select_one_onecol_txn(
-                txn=txn,
-                table="events",
-                keyvalues={"room_id": room_id, "event_id": last_read_event_id},
-                retcol="stream_ordering",
-            )
-        else:
-            # If there's no read receipt for that room, it probably means the user hasn't
-            # opened it yet, in which case use the stream ID of their join event.
-            # We can't just set it to 0 otherwise messages from other local users from
-            # before this user joined will be counted as well.
-            txn.execute(
-                """
-                SELECT stream_ordering FROM local_current_membership
-                LEFT JOIN events USING (event_id, room_id)
-                WHERE membership = 'join'
-                    AND user_id = ?
-                    AND room_id = ?
-                """,
-                (user_id, room_id),
-            )
-            row = txn.fetchone()
-
-            if row is None:
-                return 0
-
-            stream_ordering = row[0]
-
-        # Count the messages that qualify as unread after the stream ordering we've just
-        # retrieved.
-        sql = """
-            SELECT COUNT(*) FROM events
-            WHERE sender != ? AND room_id = ? AND stream_ordering > ? AND count_as_unread
-        """
-
-        txn.execute(sql, (user_id, room_id, stream_ordering))
-        row = txn.fetchone()
-
-        return row[0] if row else 0
-
 
 AllNewEventsResult = namedtuple(
     "AllNewEventsResult",