private ErrorMessage createExecutionError(ExecutionException e) {
        log.log(Level.WARNING,"Exception in " + execution + " of " + query, e.getCause());
        return ErrorMessage.createErrorInPluginSearcher("Error in '" + execution + "': " +
                                                        Exceptions.toMessageString(e.getCause()), e.getCause());
    }
Returns the execution which creates this
container-search/src/main/java/com/yahoo/search/searchchain/FutureResult.java