Single shard

[pietermartin]

Hi,

We have many tables, 50 000+. We'd like to put certain schemas on separate workers/nodes, but have no need to shard individual tables across workers.

Does it make sense to use a shard count of 1?
Will the cluster be able to be balanced?

Will we instead need to move the shards individually using citus_copy_shard_placement?

Thanks
Pieter

[marcocitus]

The cluster will be balanced when calling rebalance_table_shards, but not when tables are created, so you may need to rebalance after creating new tables. Make sure to use colocate_with in create_distributed_table for tables in the same schema, and colocate_with :='none' for the first table in a new schema.

(wish GitHub showed some visual hint for new discussion topics)

[pietermartin]

Not quite following why there is a need for rebalance_table_shards. Seeing as its going to one table there is nothing to rebalance or am I missing something?

[onurctirtir]

There is a much easier way of distributing a PostgreSQL cluster based on schemas, as of 12.0, see https://www.citusdata.com/blog/2023/07/31/schema-based-sharding-comes-to-postgres-with-citus/.