Scylla: Improve nodetool getendpoints to return shard in addition to node

[gnumoreno]

Current state:

nodetool getendpoints -- keyspace table pk1:pk2:pk3
192.168.0.10
192.168.0.11
192.168.0.12

Desired:

nodetool getendpoints -- keyspace table pk1:pk2:pk3
192.168.0.10 10
192.168.0.11 10
192.168.0.12 10

10 above being the shard

[vladzcloudius]

I like this one - this in particular would allow mapping large_partitions/rows content to corresponding shard.

However the best would be to actually have the shard info in the large_partition/row to save the hassle.

@avikivity @slivne What do you think?

[dyasny]

I wonder if the API actually exposes it

[avikivity]

I don't think we can implement getendpoints because we don't know smp::count for other nodes.

We can add it to the local large* tables.

[gnumoreno]

I like the idea of having this on large* tables as well. Let's go with this idea since Avi and Vlad are in agreement.

[haaawk]

I don't think we can implement getendpoints because we don't know smp::count for other nodes.

We can add it to the local large* tables.

smp::count is gossiped by each node and we know it. It's used in CDC

[dyasny]

@avikivity if we're going with having this information in a table, it would be an easy and extra nice UX to have the nodetool command output point the user towards that table

[slivne]

@haaawk

• can you please reference the CDC gossip info you mentioned above.
• this will force using this only after CDC is GAd wwhich is ok for master.

[slivne]

@haaawk - ping

[slivne]

@haaawk / @kbr- ping

[haaawk]

@slivne https://github.com/scylladb/scylla/blob/master/gms/application_state.hh#L65-L66

[haaawk]

Also https://github.com/scylladb/scylla/blob/052a8d036d8c5ef73cb2ace333def29accde3634/cdc/generation.cc#L200