automatic assignment / event trigger workaround

[Andrei-Pozolotin]

1. event_trigger for automatic assignment:
   https://github.com/2ndQuadrant/pglogical#automatic-assignment-of-replication-sets-for-new-tables
   works only for CREATE TABLE

2. there is a bug that prevents event_trigger form being used for DROP TABLE:
   https://www.postgresql.org/message-id/16177-053a34714817c3e1%40postgresql.org
   BUG #16177: pg_event_trigger_ddl_commands() returns empty set ...

3. here is possible solution proposed by Álvaro Herrera:
   https://www.postgresql.org/message-id/20191224161828.GA14840%40alvherre.pgsql

I wonder if it's possible for pglogical to register pg_depend entries to
the replication set, so that the repset membership is dropped alongside
the table.

[luss]

Hello Andrei,

Do you have a patch that leverages Andrei's solution to improve the basic ddl replication features avaialble in pglogical2?

[Andrei-Pozolotin]

sure, my "patch" is an application-level hack, (no triggers, no changes to pglogical) :-)

1. based on alembic
   https://alembic.sqlalchemy.org/en/latest/

2. with postgres functions
   https://gist.github.com/Andrei-Pozolotin/7bb44f13eeb26512d3c8196b14101f9d#file-setup-sql

3. with custom alembic env
   https://gist.github.com/Andrei-Pozolotin/7bb44f13eeb26512d3c8196b14101f9d#file-alembic_env-py

4. with alembic ddl create/delete intercept
   https://gist.github.com/Andrei-Pozolotin/7bb44f13eeb26512d3c8196b14101f9d#file-alembic_unit-py