It currently can happen that a sync to ElasticSearch is halted while in progress. If that happens then site search will not work until the sync is re-started manually.

We don't know yet in which specific cases it ends up in this state. Likely it happens when the sync button is pressed, but the user that pressed it closes the page before the sync is complete. The sync works in batches but depends on the browser sending a request to start the next batch.

Maybe we can add a prompt with confirmation when closing the page if a sync is in progress? Like the browser prompts you get when you have unsaved changes in the editor and try to close the page.

We could also look into a non-destructive sync that does not empty everything, but instead updates records one by one. This kind of sync could be interrupted without causing any issue.

It would be helpful if we had a record of what/who initiated a ES sync.