I'm trying to figure out if the
_update_by_query elasticsearch endpoint reindexes entire documents. I ran a batch process that generated and ran thousands of update_by_query statements. My CPU escalated after some time so I stopped running them. That was about a week ago, and my CPU is still abnormally high.
When I check the nodes in my cluster, one of them has unusually high processing percentage. I checked the hot threads against that node and it appears to still be processing update tasks. I stopped running the updates over a week ago. How could this node still be processing updates? My thinking was that it's reindexing documents that were affected by the updates.
Please share any thoughts.