Fix HTTP repl response to use minimum token (#16578)

2 files changed, 2 insertions, 1 deletions

diff --git a/changelog.d/16578.bugfix b/changelog.d/16578.bugfix
new file mode 100644

index 0000000000..4f4a0380cd
--- /dev/null
+++ b/changelog.d/16578.bugfix
@@ -0,0 +1 @@
+Fix a long-standing, exceedingly rare edge case where the first event persisted by a new event persister worker might not be sent down `/sync`.
diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py

index 7476839db5..38701aea72 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -433,7 +433,7 @@ class ReplicationEndpoint(metaclass=abc.ABCMeta):
 
         if self.WAIT_FOR_STREAMS:
             response[_STREAM_POSITION_KEY] = {
-                stream.NAME: stream.current_token(self._instance_name)
+                stream.NAME: stream.minimal_local_current_token()
                 for stream in self._streams
             }