Durable database writes about jaeger-clickhouse

[pavolloffay]

Can any of these by hadnled by ch sql driver (for instance retries)? Maybe there is some middleware for SQL client that provides these capabilities.

3. Reload connection string when requested: a user can add new shards to CH installation

Can you please explain this further? Do you mean call sql.Open when the user requests it?

[x4m]

I do not know if drivers do it.
Can you please explain this further? Do you mean call sql.Open when the user requests it?

It's important to handle cases when users change the topology of the CH cluster. Adds or removes nodes. sql.Open() is part of the solution, yes. BTW it's important to reconnect when database was restarted.

[pavolloffay]

It's important to handle cases when users change the topology of the CH cluster. Adds or removes nodes. sql.Open() is part of the solution, yes. BTW it's important to reconnect when database was restarted.

Let's say the DB plugin writes to Distributed table engine and the topology changes (e.g. added new node/shard). Is it mandatory to reconnect to DB with sql.Open? I didn't experience this when working on https://github.com/jaegertracing/jaeger-clickhouse/blob/main/guide-sharding-and-replication.md.

[x4m]

No, it's OK to connect to the remaining nodes. But, I think, eventually you need to update connection information.

[pavolloffay]

Also the storage plugin is connected to the loadbalancer and not to each individual node.

Perhaps we should mention this in our docs. @EinKrebs would you like to document this in the config?

[x4m]

I think in CH each individual node is the load balancer. And you can specify this in the connection string of the driver. But it's better to ask some CH experts here... I'll do that.