From 86e217645ef60aaf85c713b6b30effeab6834a95 Mon Sep 17 00:00:00 2001
From: Patrick Cloke <patrickc@matrix.org>
Date: Thu, 8 Sep 2022 10:43:12 -0400
Subject: [PATCH 1/2] Use upsert for receipts_graph.

---
 synapse/storage/databases/main/receipts.py | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/synapse/storage/databases/main/receipts.py b/synapse/storage/databases/main/receipts.py
index 124c70ad37b6..3838409519c3 100644
--- a/synapse/storage/databases/main/receipts.py
+++ b/synapse/storage/databases/main/receipts.py
@@ -812,7 +812,7 @@ def _insert_graph_receipt_txn(
         # FIXME: This shouldn't invalidate the whole cache
         txn.call_after(self._get_linearized_receipts_for_room.invalidate, (room_id,))
 
-        self.db_pool.simple_delete_txn(
+        self.db_pool.simple_upsert_txn(
             txn,
             table="receipts_graph",
             keyvalues={
@@ -820,17 +820,13 @@ def _insert_graph_receipt_txn(
                 "receipt_type": receipt_type,
                 "user_id": user_id,
             },
-        )
-        self.db_pool.simple_insert_txn(
-            txn,
-            table="receipts_graph",
             values={
-                "room_id": room_id,
-                "receipt_type": receipt_type,
-                "user_id": user_id,
                 "event_ids": json_encoder.encode(event_ids),
                 "data": json_encoder.encode(data),
             },
+            # receipts_graph has a unique constraint on
+            # (user_id, room_id, receipt_type), so no need to lock
+            lock=False,
         )
 
 

From 1b6609451e8785b50706841bd7a11b816a34972e Mon Sep 17 00:00:00 2001
From: Patrick Cloke <patrickc@matrix.org>
Date: Thu, 8 Sep 2022 10:44:51 -0400
Subject: [PATCH 2/2] Newsfragment

---
 changelog.d/13752.misc | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/13752.misc

diff --git a/changelog.d/13752.misc b/changelog.d/13752.misc
new file mode 100644
index 000000000000..7624861b9f4e
--- /dev/null
+++ b/changelog.d/13752.misc
@@ -0,0 +1 @@
+User an additional database query when persisting receipts.