23 posts tagged with "faq"

In version control systems like Git, a changeset represents an atomic unit of change. It groups related file modifications under a single hash, allowing them to be reviewed, applied, or reverted together.

In database migrations, a changeset is a unit of schema or data changes made up of SQL statements stored in a migration file, typically executed together in a single transaction.

Question​

How to generate an SQL schema file from an existing migrations directory to quickly set up a database for integration tests?

How do I fix the ModifySchema is not allowed when migration plan is scoped to one schema error?

When I have the same schema deployed across multiple database servers, do I need to plan and approve migrations for each database separately?

After upgrading Atlas, you might encounter an error stating "Feature X is no longer supported by this release."

For example:

Error: data.external_schema is no longer supported by this release.

This occurs when you install the community version of Atlas, which lacks some features available only in non-community builds.

When working with multiple branches and applying hotfixes directly to production, out-of-order migration conflicts may occur if migration files are created with timestamps that don't reflect the actual merge order.

The Problem​

Consider this scenario:

Initial state:

• Master branch:
  • 001_initial.sql
• Dev branch (PR pending):
  • 001_initial.sql
  • 002_add_posts.sql
  • 004_add_index.sql

After hotfix applied directly to production:

• Master branch:
  • 001_initial.sql
  • 003_hotfix_add_email.sql ← hotfix added
• Dev branch (unchanged):
  • 001_initial.sql
  • 002_add_posts.sql
  • 004_add_index.sql

After merging master into dev - the problem:

• 001_initial.sql - Applied to production
• 002_add_posts.sql - Dev-only, not applied to production
• 003_hotfix_add_email.sql - Applied to production
• 004_add_index.sql - Dev-only, not applied to production

This creates a non-linear migration history where migration files 002 and 004 were created before and after the hotfix timestamp but haven't been applied to production.

Question​

How can I resolve the pq: out of shared memory error that appears while Atlas loads my schema?

Question​

How do I manage PostgreSQL extensions with Atlas?

Question​

My revisions table lists the following versions:

mysql> SELECT * FROM  "atlas_schema_revisions";
+-------------------------+---------+-----+
| version                 | applied | ... |
+-------------------------+---------+-----+
| .atlas_cloud_identifier | 0       |     |
| 20251007053111          | 1       |     |
| 20251007051222          | 1       |     |
| 20250618084333          | 1       |     |
+-------------------------+---------+-----+

However, when I inspect the target database, the schema changes from 20250618084333 were never applied. How can I delete the latest row(s) so the revision history reflects the actual state?

Question​

What encoding is used by Atlas for schema files? How do you avoid encoding issues with PowerShell on Windows?

Answer​

Atlas uses UTF-8 to encode schema files and migration files generated by Atlas. UTF-8 is the default encoding on nearly all system terminals, but on Windows, PowerShell uses UTF-16 by default. This can cause an encoding issue when Atlas loads the schema files generated by the inspect command.