Help understanding the cluster aspects

CrateDB
1

I’m testing cratedb 4.5.0 as a solution for our data analysis needs. I’m running 3 servers all on a private vlan. Server-01 is the master right now. server-01 is importing a large dataset. server-02 and server-03 are part of the cluster, but not importing anything. I upgraded the kernel on server-03, and figured that it is part of a cluster so let’s reboot it to load the new kernel. server-01 stopped the import because server-03 left the cluster. Here’s the error message:

COPY test_client_connections FROM 'file:///opt/data/working/*client_connections.csv.gz' WITH (format = 'csv', compression = 'gzip') RETURN SUMMARY;                                               
JobKilledException[Job killed. Participating node=server-03 disconnected.]

I found this in the docs, but it doesn’t seem to work as I expected. I have to shut down cratedb on the node first, which causes the above error on the other nodes.

Is there some doc I’m missing about how to do this?

Thanks!

2

What do you mean, by that there is no import running on server-02 and 03?
If they formed a cluster, most likely also data is written to node 02 and 03.
Also the COPY statement - if not specifically excluded - will run on all nodes in the cluster [1] :wink:

If you want to remove a node from the cluster it is always best to use a graceful stop, e.g. with the decomission statement [2]

ALTER CLUSTER DECOMMISSION <node>

[1] COPY FROM — CrateDB: Reference
[2] ALTER CLUSTER — CrateDB: Reference

3

Thanks for the pointers. The import is literally only running on server-01 via crash inside tmux. The source data csv zipfiles only exist on server-01. I can see the tables/shards spread across the cluster. I just didn’t expect the loss from 1 of 3 servers to not fail gracefully. As in, “1 of 3 is gone, ok carry on until t’s back”.

I’ll do the alter cluster statement before rebooting cluster members.

Thanks!