log.trace("registerSubsegment(" + subSegmentName + ")");
// check parent authority
if (parentAuthority == null) throw new NullPointerException();
if (! (parentAuthority instanceof DbAuthority)) throw new StoreNotFoundException("Parent authority is not from this store.");
// check if the parent authority overrides the CREATE pipeline. if not, use the default.
ServerConfig serverConfig = ServerConfigFactory.getSingleton();
PipelineRegistry pipelineRegistry = (serverConfig == null) ? null : serverConfig.getPipelineRegistry();