lncfg: readd global lock for postgres and the channeldb_kv table

Author: ziggie1984

lncfg/db.go

@@ -398,18 +398,28 @@ func (db *DB) GetBackends(ctx context.Context, chanDBPath,
 		// Convert the sqldb PostgresConfig to a kvdb postgres.Config.
 		// This is a temporary measure until we migrate all kvdb SQL
 		// users to native SQL.
-		postgresConfig := GetPostgresConfigKVDB(db.Postgres)
+		postgresConfigChannelDB := GetPostgresConfigKVDB(db.Postgres)
+
+		// The channel DB is still not robust enough to run with
+		// multiple writers therefore we set the global lock for the
+		// channel db in particular.
+		//
+		// TODO(ziggie): SHould be removed as soon as the revocation log
+		// is migrated to native SQL.
+		postgresConfigChannelDB.WithGlobalLock = true
 
 		postgresBackend, err := kvdb.Open(
 			kvdb.PostgresBackendName, ctx,
-			postgresConfig, NSChannelDB,
+			postgresConfigChannelDB, NSChannelDB,
 		)
 		if err != nil {
 			return nil, fmt.Errorf("error opening postgres graph "+
 				"DB: %v", err)
 		}
 		closeFuncs[NSChannelDB] = postgresBackend.Close
 
+		postgresConfig := GetPostgresConfigKVDB(db.Postgres)
+
 		postgresMacaroonBackend, err := kvdb.Open(
 			kvdb.PostgresBackendName, ctx,
 			postgresConfig, NSMacaroonDB,