Geo: Improve replication status. Relying on pg_stat_wal_receiver

ee/lib/gitlab/geo/health_check.rb

@@ -7,7 +7,7 @@ module Gitlab
         return '' unless Gitlab::Geo.secondary?
         return 'The Geo database configuration file is missing.' unless Gitlab::Geo.geo_database_configured?
         return 'The Geo node has a database that is not configured for streaming replication with the primary node.' unless self.database_secondary?
-        return 'The Geo node does not appear to be replicating data from the primary node.' unless self.db_replication_lag_seconds.present?
+        return 'The Geo node does not appear to be replicating data from the primary node.' unless self.streaming_active?
 
         database_version  = self.get_database_version.to_i
         migration_version = self.get_migration_version.to_i
@@ -76,6 +76,18 @@ module Gitlab
 
         lag.present? ? lag.to_i : lag
       end
+
+      def self.streaming_active?
+        # Get a streaming status
+        # This only works for Postgresql 9.6 and greater
+        status =
+          ActiveRecord::Base.connection.execute('
+          SELECT * FROM pg_stat_wal_receiver;')
+          .first
+          .fetch('status')
+
+        status == 'streaming'
+      end
     end
   end
 end