Eugene Documentation

✅ Eugene trace report

Script name: examples/W12/bad/1.sql

✅ Statement number 1 for 10ms

-- 1.sql
create table authors(
    id integer generated always as identity
        primary key,
    name text,
    email text
)

Locks at start

No locks held at the start of this statement.

New locks taken

No new locks taken by this statement.

❌ Eugene trace report

Script name: examples/W12/bad/2.sql

✅ Statement number 1 for 10ms

-- 2.sql
set lock_timeout = '2s'

Locks at start

No locks held at the start of this statement.

New locks taken

No new locks taken by this statement.

❌ Statement number 2 for 10ms

alter table authors
    alter column name set not null

Locks at start

No locks held at the start of this statement.

New locks taken

Triggered rules

E2: Validating table with a new NOT NULL column

The column name in the table public.authors was changed to NOT NULL. If there is a CHECK (name IS NOT NULL) constraint on public.authors, this is safe. Splitting this kind of change into 3 steps can make it safe:

1. Add a CHECK (name IS NOT NULL) NOT VALID; constraint on public.authors.
2. Validate the constraint in a later transaction, with ALTER TABLE public.authors VALIDATE CONSTRAINT ....
3. Make the column NOT NULL

✅ Statement number 3 for 10ms

-- eugene: ignore E2, E4
alter table authors
    alter column email set not null

Locks at start

New locks taken

No new locks taken by this statement.