https://github.com/phillbaker/pg_migrate

Reorganize tables in PostgreSQL databases with minimal locks
https://github.com/phillbaker/pg_migrate

migrations pg postgres postgresql

Last synced: about 2 months ago
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Reorganize tables in PostgreSQL databases with minimal locks

• Host: GitHub
• URL: https://github.com/phillbaker/pg_migrate
• Owner: phillbaker
• License: bsd-3-clause
• Created: 2022-01-21T02:30:08.000Z (almost 3 years ago)
• Default Branch: master
• Last Pushed: 2024-02-11T23:09:38.000Z (11 months ago)
• Last Synced: 2024-02-12T00:25:12.497Z (11 months ago)
• Topics: migrations, pg, postgres, postgresql
• Language: C
• Homepage:
• Size: 1 MB
• Stars: 8
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md

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README

        
# pg_migrate -- Perform schema changes in PostgreSQL with minimal locks

- Download: https://github.com/phillbaker/pg_migrate/releases

- Development: https://github.com/phillbaker/pg_migrate

- Bug Reports: https://github.com/phillbaker/pg_migrate/issues

## About

pg_migrate is a PostgreSQL extension and CLI which lets you make schema

changes to tables and indexes. Unlike `ALTER TABLE` it works online, without

holding a long lived exclusive lock on the processed tables during the

migration. It builds a copy of the target table and swaps them.

Please check the documentation (in the ``doc`` directory or online) for

installation and usage instructions.

Forked from the excellent pg_repack project (https://reorg.github.io/pg_repack).

## Supported Postgres Versions

Postgres >= 9.6

## Installation

### Ubuntu/Debian

Use `apt-get` to install the package matching the Postgres version (`postgresql--pg_migrate`) being run from [this repo's APT repository](https://github.com/phillbaker/pg_migrate/releases/tag/apt-release-amd64).

To add to your `/etc/apt/sources.list.d`, add the signing GPG key, and update the package DB, run:

```

curl -L https://github.com/phillbaker/pg_migrate/releases/download/apt-release-amd64/apt-add-repo | sh

```

Then to install, for example, for Postgres 10:

```

apt-get install -y postgresql-10-pg_migrate

```

Load the pg_migrate Postgres extension in the database you want to work on:

```

psql -c "DROP EXTENSION IF EXISTS pg_migrate cascade; CREATE EXTENSION pg_migrate" -d postgres

```

### Mac

Use `homebrew` to install the package matching the Postgres version being used.

```

brew tap phillbaker/pg_migrate https://github.com/phillbaker/pg_migrate

brew install pg_migrate_postgresql@10

# follow the post install instructions if you're running postgres on your local machine

```

## Examples

### Change the type of a column

```

pg_migrate --table=my_table --alter='ALTER COLUMN id TYPE bigint' # Add --execute to run

```

### Add a column with a default (non-nullable)

```

pg_migrate --table=my_table --alter='ADD COLUMN foo integer NOT NULL DEFAULT 42' # Add --execute to run

```

## Known Limitations

* Unique constraints are converted into unique indexes, [they are equivalent in Postgres](https://stackoverflow.com/questions/23542794/postgres-unique-constraint-vs-index). However, this may be an unexpected change.

* Index names on the target table and foreign key constraints are changed during the migration.

  * If the generated names are > 63 characters, this will likely break

* If the target table is used in views, those objects will continue to reference the original table - this is not supported currently.

  * If the target table is used in stored procedures, those functions are stored as text so are not linked through object IDs and will reference the migrated table.

* DDL to drop columns or add columns without a default is not currently supported

* Hosted PG databases (RDS, Cloud SQL) are not supported because they do not allow installing custom extensions.