Upgrade to 5.x, some of my existing searches are taking longer to return results. Not as many scheduled searches are running on time. Could fetch_remote_search_log setting be a factor?

After upgrading to 5.x, I noticed that some of my searches are taking a longer time to return results than prior. Search performance has slowed down and not as many scheduled searches are running on time. Could the parameter fetch_remote_search_log be a factor? What is it?