Add a configuration setting for the dummy event threshold (#7422)

Add dummy_events_threshold which allows configuring the number of forward extremities a room needs for Synapse to send forward extremities in it.

1 files changed, 12 insertions, 0 deletions

diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml

index fc970986c6..98ead7dc0e 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -253,6 +253,18 @@ listeners:
   #  bind_addresses: ['::1', '127.0.0.1']
   #  type: manhole
 
+# Forward extremities can build up in a room due to networking delays between
+# homeservers. Once this happens in a large room, calculation of the state of
+# that room can become quite expensive. To mitigate this, once the number of
+# forward extremities reaches a given threshold, Synapse will send an
+# org.matrix.dummy_event event, which will reduce the forward extremities
+# in the room.
+#
+# This setting defines the threshold (i.e. number of forward extremities in the
+# room) at which dummy events are sent. The default value is 10.
+#
+#dummy_events_threshold: 5
+
 
 ## Homeserver blocking ##