Add a unique constraint on the room hosts table

1 files changed, 2 insertions, 1 deletions

diff --git a/synapse/storage/schema/im.sql b/synapse/storage/schema/im.sql

index 7f4e758892..e92f21ef3b 100644
--- a/synapse/storage/schema/im.sql
+++ b/synapse/storage/schema/im.sql
@@ -98,5 +98,6 @@ CREATE TABLE IF NOT EXISTS rooms(
 
 CREATE TABLE IF NOT EXISTS room_hosts(
     room_id TEXT NOT NULL,
-    host TEXT NOT NULL
+    host TEXT NOT NULL,
+    CONSTRAINT room_hosts_uniq UNIQUE (room_id, host) ON CONFLICT IGNORE
 );