> > Which client operations could trigger schema change at node level? Do you > mean that for ex creating a new table trigger a schema change globally, not > only at KS/table single level? > Yes, any DDL statement (creating tables, altering, dropping, etc) triggers a schema change across the cluster (globally). All nodes need to be told of this schema change.
> I don't have schema changes, except keyspaces and tables creations. But > they are done from multiple sources indeed. With a "create if not exists" > statement, on demand. Thanks you for your answer, I will try to see if I > could precreate them then. > Yep, definitely do that. You don't want to be issuing simultaneous create statements from different clients. IF NOT EXISTS won't necessarily catch all cases. > As for the schema mismatch, what is the best way of fixing that issue? > Could Cassandra recover from that on its own or is there a nodetool command > to force schema agreement? I have heard that we have to restart the nodes 1 > by 1, but it seems a very heavy procedure for that. > A rolling restart is usually enough to fix the issue. You might want to repair afterwards, and check that data didn't make it to different versions of the table on different nodes (in which case some more intervention may be necessary to save that data). -- raft.so - Cassandra consulting, support, and managed services
