PostgreSQL migration failed due to unsupported type or constraint syntax

What this failure means

A database migration failed because the PostgreSQL version in CI does not support a type or constraint syntax used in the migration (e.g. the built-in JSON type requires PostgreSQL 9.2+, and NOT VALID constraints require 9.1+). Subsequent migration commands are skipped because the transaction is aborted.

Symptoms

Faultline looks for one or more of these log fragments:

type "json" does not exist
CHECK constraints cannot be marked NOT VALID

Diagnosis

The test suite runs migrations against a PostgreSQL instance that is older than the migration requires. The first failing statement aborts the transaction and causes all remaining migration commands to emit “current transaction is aborted” errors.

Common triggers:

• type "json" does not exist — the migration uses the built-in JSON type, which was added in PostgreSQL 9.2. Any version below 9.2 will fail on this.
• CHECK constraints cannot be marked NOT VALID — the NOT VALID modifier for CHECK constraints was added in PostgreSQL 9.1.
• The CI PostgreSQL service container is pinned to an old image tag (e.g. postgres:9.0 or unversioned postgres:latest that resolved to an old image when first written).

Fix steps

1. Note the failing migration statement (e.g. type "json" does not exist).
2. Check the PostgreSQL version running in CI:

   psql --version
   # or in CI logs: look for "PostgreSQL X.Y" in the service startup output
   

3. Update the CI service to PostgreSQL 9.2 or later (13+ is recommended):

   # GitHub Actions
   services:
     postgres:
       image: postgres:14
   # Travis CI
   addons:
     postgresql: "14"
   

4. If the project must support older PostgreSQL, replace the JSON type with TEXT and validate format in application code, or use the hstore extension for key-value data.
5. Re-run migrations after the version bump:

   alembic upgrade head
   # or
   python manage.py migrate
   

Validation

• Confirm the PostgreSQL version in CI is 9.2 or later.
• Re-run the test suite. No type "json" does not exist or current transaction is aborted errors should appear.
• make test passes cleanly.

Why it matters

When a migration fails inside a transaction, the entire transaction is aborted. Every subsequent migration command fails with “current transaction is aborted, commands ignored until end of transaction block” — making the log appear to have many failures when the root cause is a single version-incompatibility at the top. Identifying the first real error is essential to resolving the failure quickly.

Prevention

• Pin the CI PostgreSQL image to an explicit major version (e.g. postgres:14).
• Document the minimum supported PostgreSQL version in the project README.
• Test migrations locally against the same version used in CI using Docker.

Try it locally

psql --version
docker run --rm postgres:9.0 psql -c 'SELECT 1::json'
python manage.py migrate --run-syncdb
alembic upgrade head

How Faultline detects it

Use faultline explain postgres-version-incompatible-migration to see the full playbook.

faultline analyze build.log
faultline explain postgres-version-incompatible-migration

Generated from playbooks/bundled/log/test/postgres-version-incompatible-migration.yaml. Do not edit directly.