ALC-9001: Not supported here

The feature you used needs something this server, database or table does not have. Nothing ran.

What you see

One of these messages, where you used the feature:

• A generic plan needs PostgreSQL 16.: explaining with Generic plan on an older server.
• HypoPG is not installed in this database, so the index must be built to compare: use Index this filter, and the plan explains again once it is applied.: Try without building on a plan.
• public.events has no primary key or unique index over NOT NULL columns, so a row cannot be identified safely. Add a key, or change it with SQL.: committing a row edit on a table without a usable key.
• public.events has no key, so its rows cannot be read back: reviewing a stale change on such a table.
• This database does not support … or No database module is available.

On a table without a usable key, the grid also says Rows here are read-only.

Why it happens

• Generic plan uses EXPLAIN (GENERIC_PLAN), which Postgres added in version 16.
• Try without building asks the planner about an index that does not exist yet, through the HypoPG extension. Without it, the index has to be built to compare plans.
• Alcuin edits a row by naming it with its key. Without a primary key, or a unique index whose columns are all NOT NULL, two rows can look the same, so an edit could change the wrong one.
• This database does not support … and No database module is available. mean a part of Alcuin is missing. They should not appear with Postgres.

What to do

For Generic plan: explain without it, or upgrade the server to Postgres 16 or later. Supported Postgres versions lists the features that need a newer server.

For Try without building: install HypoPG on the server and run CREATE EXTENSION hypopg; in the database, if your provider offers it. Otherwise use Index this filter, which builds the index and explains the plan again once it is applied.

To edit a table without a key:

1. Add a key, if the table should have one: ALTER TABLE public.events ADD PRIMARY KEY (id);. See Constraints.
2. Or make the change with SQL: select a row and choose Open as query, beside Rows here are read-only. Alcuin drafts an UPDATE in a new query tab that matches the row on every column’s value. As its first line says, it matches every row with exactly those values, so check the count before you run it.

For This database does not support … or No database module is available.: report it as described in ALC-9005.

Internal name

The engine reports this as ENGINE_UNSUPPORTED. Quote either name in an issue.