2 files changed, 3 insertions, 1 deletions
diff --git a/synapse/replication/slave/storage/client_ips.py b/synapse/replication/slave/storage/client_ips.py
index 352c9a2aa8..fedf7a3188 100644
--- a/synapse/replication/slave/storage/client_ips.py
+++ b/synapse/replication/slave/storage/client_ips.py
@@ -42,6 +42,8 @@ class SlavedClientIpStore(BaseSlavedStore):
         if last_seen is not None and (now - last_seen) < LAST_SEEN_GRANULARITY:
             return
 
+        self.client_ip_last_seen.prefill(key, now)
+
         self.hs.get_tcp_replication().send_user_ip(
             user_id, access_token, ip, user_agent, device_id, now
         )
diff --git a/synapse/replication/tcp/streams.py b/synapse/replication/tcp/streams.py
index 4c60bf79f9..07d99dd63c 100644
--- a/synapse/replication/tcp/streams.py
+++ b/synapse/replication/tcp/streams.py
@@ -33,7 +33,7 @@ import logging
 logger = logging.getLogger(__name__)
 
 
-MAX_EVENTS_BEHIND = 10000
+MAX_EVENTS_BEHIND = 500000
 
 
 EventStreamRow = namedtuple("EventStreamRow", (