Does anyone have any experience building with Citus they can share?
I've been reading about it for years and it's always sounded very impressive to me - the magic sauce that you can sprinkle on regular PostgreSQL to have it scale horizontally - but I haven't yet had the opportunity to try it.
I've yet to make it out of the lab. The failover solutions seem to be A-B rather than A-B-DR. That is, you can have a primary and a replica (probably in the same DC/AZ), but you can't do a primary, a replica, and another replica in another datacenter that can function on its own (in a DR capacity).
Citus uses physical replication for worker and coordinator nodes, and things start getting complicated when you're trying to monitor the status of all the replicas. With vanilla PostgreSQL, you don't have this issue. I'm guessing that they solve this in Azure with block-device primitives at the storage level or something along those lines? It's probably not insurmountable to do it yourself, but we're not yet at the grip-n-rip enterprise offering.
Making HA easier while self-hosting is definitely something that's high on our list of future improvements. I wouldn't be surprised if there will be some announcements regarding this in the coming year. One of the main issues (imo) is configuring HA for PG isn't easy, even when using regular PG. And this becomes even more complicated in the case of Citus, because you're effectively running multiple PG servers, all of which you need to configure HA for.
For my understanding about the multi-region DR capability you would want: Do you want to be able to write to the DR region all the time? Or do you want to be able to switch over to the DR region in case the main DC is down?
Same here, wanna see some production usage testimonials. Plus has someone compared it to CockroachDB? I understand they are two different technologies with broader strokes of same idea of scaling Postgres horizontally but still would love to see some sort of comparison and differences.
I've been reading about it for years and it's always sounded very impressive to me - the magic sauce that you can sprinkle on regular PostgreSQL to have it scale horizontally - but I haven't yet had the opportunity to try it.