Note on PGDATA changes for PostgreSQL 18+ #2582
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tianon
reviewed
Jun 4, 2025
postgres/content.md
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| @@ -96,7 +96,9 @@ See the PostgreSQL documentation on [`pg_hba.conf`](https://www.postgresql.org/d | |||
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| ### `PGDATA` | |||
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| > **Important Note:** Mount the data volume at `/var/lib/postgresql/data` and not at `/var/lib/postgresql` because mounts at the latter path WILL NOT PERSIST database data when the container is re-created. The Dockerfile that builds the image declares a volume at `/var/lib/postgresql/data` and if no data volume is mounted at that path then the container runtime will automatically create an [anonymous volume](https://docs.docker.com/engine/storage/#volumes) that is not reused across container re-creations. Data will be written to the anonymous volume rather than your intended data volume and won't persist when the container is deleted and re-created. | |||
| > **Important Change:** the `PGDATA` environment variable of the image was changed to be version specific in PostgreSQL 18 and above. For 18 it is `/var/lib/postgresql/18/docker`. Later versions will replace `18` with their respective major version (e.g., `/var/lib/postgresql/19/docker` for PostgreSQL `19.x`). The defined `VOLUME` was changed in 18 and above to `/var/lib/postgresql`. Mounts and volumes should be targeted at the updated location. This will allow users upgrading between PostgreSQL major releases to use the faster `--link` when running `pg_upgrade` and mounting `/var/lib/postgresql`. | |||
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IMO we should link this explicitly over to docker-library/postgres#1259 somewhere. I wonder if we should also add more explicit guidance around setting PGDATA explicitly, either to avoid this change or to opt into this change sooner?
Suggested change
| > **Important Change:** the `PGDATA` environment variable of the image was changed to be version specific in PostgreSQL 18 and above. For 18 it is `/var/lib/postgresql/18/docker`. Later versions will replace `18` with their respective major version (e.g., `/var/lib/postgresql/19/docker` for PostgreSQL `19.x`). The defined `VOLUME` was changed in 18 and above to `/var/lib/postgresql`. Mounts and volumes should be targeted at the updated location. This will allow users upgrading between PostgreSQL major releases to use the faster `--link` when running `pg_upgrade` and mounting `/var/lib/postgresql`. | |
| > **Important Change:** [the `PGDATA` environment variable of the image was changed to be version specific in PostgreSQL 18 and above](https://github.com/docker-library/postgres/pull/1259). For 18 it is `/var/lib/postgresql/18/docker`. Later versions will replace `18` with their respective major version (e.g., `/var/lib/postgresql/19/docker` for PostgreSQL `19.x`). The defined `VOLUME` was changed in 18 and above to `/var/lib/postgresql`. Mounts and volumes should be targeted at the updated location. This will allow users upgrading between PostgreSQL major releases to use the faster `--link` when running `pg_upgrade` and mounting `/var/lib/postgresql`. | |
| Users who wish to opt-in to this change on older releases can do so by setting `PGDATA` explicitly (`--env PGDATA=/var/lib/postgresql/17/docker --volume some-postgres:/var/lib/postgresql`). To migrate pre-existing data, adjust the volume's folder structure appropriately first (moving all database files into a `PG_MAJOR/docker` subdirectory). |
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Ready to go once we merge docker-library/postgres#1344 and docker-library/postgres#1259. |
tianon
approved these changes
Jun 5, 2025
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Document docker-library/postgres#1259