Plan wants to change a column that hasn't changed.

[Thxsoft64]

Consider this dump (I added Create Extension so it would work witout claiming they didn't exist):

--
-- pgschema database dump
--

-- Dumped from database version PostgreSQL 17.7
-- Dumped by pgschema version 1.6.2

CREATE EXTENSION IF NOT EXISTS "citext" SCHEMA public;
CREATE EXTENSION IF NOT EXISTS "uuid-ossp" SCHEMA public;
CREATE EXTENSION IF NOT EXISTS pg_trgm SCHEMA public;

CREATE TABLE IF NOT EXISTS geotab_database (
    name citext NOT NULL,
    active boolean DEFAULT true NOT NULL,
    id uuid DEFAULT uuid_generate_v1mc(),
    api_password text,
    CONSTRAINT geotab_database_pk PRIMARY KEY (id)
);

Then run plan, I get this:

Plan: 1 to modify.

Summary by type:
  tables: 1 to modify

Tables:
  ~ geotab_database
    ~ id (column)

DDL to be executed:
--------------------------------------------------

ALTER TABLE geotab_database ALTER COLUMN id SET DEFAULT public.uuid_generate_v1mc();

Changing to id uuid DEFAULT public.uuid_generate_v1mc() didn't fix it.

[tianzhou]

@Thxsoft64 Can you clarify the before and after schema?

[Thxsoft64]

I tried again with the --plan-* commands so I could get rid of my extensions.

Before schema:

--
-- pgschema database dump
--

-- Dumped from database version PostgreSQL 17.7
-- Dumped by pgschema version 1.6.2

CREATE TABLE IF NOT EXISTS geotab_database (
    name citext NOT NULL,
    active boolean DEFAULT true NOT NULL,
    id uuid DEFAULT uuid_generate_v1mc(),
    api_password text,
    CONSTRAINT geotab_database_pk PRIMARY KEY (id)
);

After schema (the same file, no changes at all):

--
-- pgschema database dump
--

-- Dumped from database version PostgreSQL 17.7
-- Dumped by pgschema version 1.6.2

CREATE TABLE IF NOT EXISTS geotab_database (
    name citext NOT NULL,
    active boolean DEFAULT true NOT NULL,
    id uuid DEFAULT uuid_generate_v1mc(),
    api_password text,
    CONSTRAINT geotab_database_pk PRIMARY KEY (id)
);

Three other files I tested it with said there were no changes. So I don't get why it fails.

Here's the DDL generated by Rider.

create table public.geotab_database
(
    name         citext                               not null,
    active       boolean default true                 not null,
    id           uuid    default uuid_generate_v1mc() not null
        constraint geotab_database_pk
            primary key,
    api_password text
);

alter table public.geotab_database    owner to postgres;
create index geotab_database_active_idx   on public.geotab_database (active);
create index geotab_database_name_idx    on public.geotab_database (name);
create index geotab_database_name_idx1    on public.geotab_database using gin (lower(name::text) public.gin_trgm_ops);

[Thxsoft64]

To be clear, I have four schemas. Three say there are no changes which is expected.
The only one that fails is the the public schema.

[Thxsoft64]

Further. this has exactly the same id definition and works fine so it seems to be something to do with being the default schema.
The other schemas are NOT in the schema search path. The search path is the PostgreSQL default.

--
-- pgschema database dump
--

-- Dumped from database version PostgreSQL 17.7
-- Dumped by pgschema version 1.6.2

CREATE TABLE IF NOT EXISTS lookup (
    geotab_database_name public.citext NOT NULL,
    serial_number public.citext NOT NULL,
    id uuid DEFAULT public.uuid_generate_v1mc(),
    CONSTRAINT driver_key_lookup_pk PRIMARY KEY (id)
);

[Thxsoft64]

I did an 'apply' which said it was successful. There's no visible change to the table. And generating a plan again says it wants to update the same column again.

The plan JSON if interested.

{
  "version": "1.0.0",
  "pgschema_version": "1.6.2",
  "created_at": "2026-02-07T16:49:16+10:30",
  "source_fingerprint": {
    "hash": "b51e294054091daf10c792ba3ef35865d3bb7e875f184fb8e7fbfef60bd239e6"
  },
  "groups": [
    {
      "steps": [
        {
          "sql": "ALTER TABLE geotab_database ALTER COLUMN id SET DEFAULT public.uuid_generate_v1mc();",
          "type": "table.column",
          "operation": "alter",
          "path": "public.geotab_database.id"
        }
      ]
    }
  ]
}