From cc8da2c5ed0cecc771919d76533704a04de9a41e Mon Sep 17 00:00:00 2001
From: Erik Johnston <erikj@element.io>
Date: Wed, 2 Jul 2025 15:02:12 +0100
Subject: [PATCH] Log the room ID we're purging state for (#18625)

So we can see what we're deleting.
---
 changelog.d/18625.misc                      | 1 +
 synapse/storage/controllers/purge_events.py | 7 +++++++
 2 files changed, 8 insertions(+)
 create mode 100644 changelog.d/18625.misc

diff --git a/changelog.d/18625.misc b/changelog.d/18625.misc
new file mode 100644
index 000000000..f2672864c
--- /dev/null
+++ b/changelog.d/18625.misc
@@ -0,0 +1 @@
+Log the room ID we're purging state for.
diff --git a/synapse/storage/controllers/purge_events.py b/synapse/storage/controllers/purge_events.py
index c2d4bf829..df3f264b0 100644
--- a/synapse/storage/controllers/purge_events.py
+++ b/synapse/storage/controllers/purge_events.py
@@ -34,6 +34,7 @@ from synapse.metrics.background_process_metrics import wrap_as_background_proces
 from synapse.storage.database import LoggingTransaction
 from synapse.storage.databases import Databases
 from synapse.types.storage import _BackgroundUpdates
+from synapse.util.stringutils import shortstr
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
@@ -167,6 +168,12 @@ class PurgeEventsStorageController:
                 break
 
             (room_id, groups_to_sequences) = next_to_delete
+
+            logger.info(
+                "[purge] deleting state groups for room %s: %s",
+                room_id,
+                shortstr(groups_to_sequences.keys(), maxitems=10),
+            )
             made_progress = await self._delete_state_groups(
                 room_id, groups_to_sequences
             )