This sure sounds similar to the issue I've been tracking here:
Interestingly enough, our daily process is to re-index the same data to a new daily index and then swap aliases... we do so little indexing outside of the nightly index that I couldn't honestly say if we're seeing index slow down but we are definitely seeing query slowdowns because of all the massive CPU ES uses for no reason until we restart all of the nodes (our ES cluster is 99.99% searching).
Apache, Apache Lucene, Apache Hadoop, Hadoop, HDFS and the yellow elephant
logo are trademarks of the
Apache Software Foundation
in the United States and/or other countries.