From e605ae2e747f6fad3248b308f852cece35774104 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Sun, 24 Dec 2023 11:20:43 +0000
Subject: [PATCH 1/2] Split up deleting devices into batches

---
 synapse/storage/databases/main/devices.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/synapse/storage/databases/main/devices.py b/synapse/storage/databases/main/devices.py
index 66fabf4f764..ae914298fbc 100644
--- a/synapse/storage/databases/main/devices.py
+++ b/synapse/storage/databases/main/devices.py
@@ -1794,7 +1794,7 @@ async def delete_devices(self, user_id: str, device_ids: List[str]) -> None:
             device_ids: The IDs of the devices to delete
         """
 
-        def _delete_devices_txn(txn: LoggingTransaction) -> None:
+        def _delete_devices_txn(txn: LoggingTransaction, device_ids: List[str]) -> None:
             self.db_pool.simple_delete_many_txn(
                 txn,
                 table="devices",
@@ -1811,7 +1811,11 @@ def _delete_devices_txn(txn: LoggingTransaction) -> None:
                 keyvalues={"user_id": user_id},
             )
 
-        await self.db_pool.runInteraction("delete_devices", _delete_devices_txn)
+        for batch in batch_iter(device_ids, 100):
+            await self.db_pool.runInteraction(
+                "delete_devices", _delete_devices_txn, batch
+            )
+
         for device_id in device_ids:
             self.device_id_exists_cache.invalidate((user_id, device_id))
 

From ae3761a5e9738d5b3c202fd43f7e60dad7483d8d Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Sun, 24 Dec 2023 11:21:41 +0000
Subject: [PATCH 2/2] Newsfile

---
 changelog.d/16766.misc | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/16766.misc

diff --git a/changelog.d/16766.misc b/changelog.d/16766.misc
new file mode 100644
index 00000000000..ded77a11c40
--- /dev/null
+++ b/changelog.d/16766.misc
@@ -0,0 +1 @@
+Split up deleting devices into batches.