mirror of
https://github.com/scylladb/scylladb.git
synced 2026-04-20 16:40:35 +00:00
df64985a4e
Current protocol extension that sends tablet info to drivers only does that if the driver selects a non-replica coordinator for a routable request. It works well if some node on the replica list is replaced by other node, or if some replicas are removed from the list. Driver will at some point send a request to stale replica, and receive new list in response. The issue is with extending the list with new replicas. In that case old replicas are all still correct, so driver will not select any wrong replica, and will not receive the new list. As far as I know that only scenario where this could happen is RF increase. It could be to some degree worked around in the drivers, but it would add significant complexity (definitely more than any other invalidations we introduced) while still not being ideal solution. This scenario should be rare enough, and the consequences of not handling it minor enough (new replicas not being used as coordinators) that it does not warrant driver-side solution. Instead this commit adds info about this to documentation, advising users to restart applications after replica lists are extended. It is worth noting that if new tablet feedback protocol extension is implemented then this problem goes away. See issue #21664. Closes scylladb/scylladb#23447
