Add template schemas for easier distributed schema management about citus HOT 3 OPEN

This was something we were anticipating that there could be a need for this, and we wanted to wait until hearing an explicit user ask about that, thank you for opening this issue!

To better understand your need, would it be enough to replicate only table level DDLs from template schemas to corresponding tables in actual schemas (ALTER TABLE), or would you need any other kind of DDLs to be replicated, such as CREATE INDEX, or any other type (VACUUM, TRUNCATE, something else)?

from citus.

I could imagine that we add a GUC that specifies which template schema is requested to be used when creating a new schema, as in:

SET citus.effective_template_schema_name = "template_schema_1";

Then the CREATE SCHEMA commands that follows this statement directly inherit table structures defined in template_schema_1 as well as following table structure changes (ALTER TABLE .., CREATE INDEX) that happens in template_schema_1. This probably also requires disallowing individual schema changes in the schemas that inherit their structure from a template one?

Is my understanding correct? DDLs other than ALTER TABLE / CREATE INDEX are needed?

from citus.

I am not familiar with all the operations you currently support with row based, but it would make sense to have this function in a similar way for consistency sake. I would think at a minimum you would need:

Table: create, alter, drop
View: create, drop
Function: create, replace, drop
Index: create, drop

from citus.