We observed that Indexing stopped on our ES cluster while we were running the curl command to clear up the field data cache. The field data cache was using ~1 GB on each node(54 data node cluster) while the total heap allocated to ES is 30G. Clearing up the cache took us around 2 minutes and indexing stopped for 2 minutes.
I'm unable to understand how clearing up the cache caused indexing to stop? I'm more concerned because this happened on our production cluster, and would like to know if there are any configurations that must be set before clearing the cache to prevent this in future.