diff --git a/install/schema_postgres.sql b/install/schema_postgres.sql
index ceee30430..f0c41dc2a 100644
--- a/install/schema_postgres.sql
+++ b/install/schema_postgres.sql
@@ -1052,7 +1052,7 @@ create index "reg_uid" on register ("uid");
 CREATE TABLE "session" (
   "id" serial,
   "sid" text NOT NULL,
-  "sess_data" text NOT NULL,
+  "sess_data" text NOT NULL DEFAULT '',
   "expire" numeric(20)  NOT NULL,
   PRIMARY KEY ("id")
 );