Hey there. You should be able initiate a recalculation of index ranges through Graylog’s API using the /system/indices/ranges/rebuild endpoint (see Problem with recalculate index by curl)
I’ll note that there seems to be a difference between the /api/system/indices/ranges/rebuild API in Graylog and the /_refresh API in Elasticsearch. To quote the API browser:
This triggers a systemjob that scans every index and stores meta information about what indices contain messages in what timeranges. It atomically overwrites already existing meta information.
With regard to the refresh API:
A refresh makes all operations performed on an index since the last refresh available for search.
There’s also a word of caution that performing a forced refresh in Elasticsearch is resource-intensive, which may be what’s causing Graylog to show a loading state.
If you need to recalculate the index ranges (not update index operations), I’d recommend using the rebuild endpoint, which should do a much more useful job of getting the data readable by Graylog.