diff --git a/synapse/storage/databases/main/relations.py b/synapse/storage/databases/main/relations.py
index 2bbf6d6a95..40760fbd1b 100644
--- a/synapse/storage/databases/main/relations.py
+++ b/synapse/storage/databases/main/relations.py
@@ -13,7 +13,7 @@
# limitations under the License.
import logging
-from typing import Optional
+from typing import Optional, Tuple
import attr
@@ -269,6 +269,63 @@ class RelationsWorkerStore(SQLBaseStore):
return await self.get_event(edit_id, allow_none=True)
+ @cached()
+ async def get_thread_summary(
+ self, event_id: str
+ ) -> Tuple[int, Optional[EventBase]]:
+ """Get the number of threaded replies, the senders of those replies, and
+ the latest reply (if any) for the given event.
+
+ Args:
+ event_id: The original event ID
+
+ Returns:
+ The number of items in the thread and the most recent response, if any.
+ """
+
+ def _get_thread_summary_txn(txn) -> Tuple[int, Optional[str]]:
+ # Fetch the count of threaded events and the latest event ID.
+ # TODO Should this only allow m.room.message events.
+ sql = """
+ SELECT event_id
+ FROM event_relations
+ INNER JOIN events USING (event_id)
+ WHERE
+ relates_to_id = ?
+ AND relation_type = ?
+ ORDER BY topological_ordering DESC, stream_ordering DESC
+ LIMIT 1
+ """
+
+ txn.execute(sql, (event_id, RelationTypes.THREAD))
+ row = txn.fetchone()
+ if row is None:
+ return 0, None
+
+ latest_event_id = row[0]
+
+ sql = """
+ SELECT COALESCE(COUNT(event_id), 0)
+ FROM event_relations
+ WHERE
+ relates_to_id = ?
+ AND relation_type = ?
+ """
+ txn.execute(sql, (event_id, RelationTypes.THREAD))
+ count = txn.fetchone()[0]
+
+ return count, latest_event_id
+
+ count, latest_event_id = await self.db_pool.runInteraction(
+ "get_thread_summary", _get_thread_summary_txn
+ )
+
+ latest_event = None
+ if latest_event_id:
+ latest_event = await self.get_event(latest_event_id, allow_none=True)
+
+ return count, latest_event
+
async def has_user_annotated_event(
self, parent_id: str, event_type: str, aggregation_key: str, sender: str
) -> bool:
|
