Upgrade PostgreSQL to v18 with updated volume mount path

README.md

@@ -107,6 +107,19 @@ Redash for redundancy. You will also need to tweak the number of workers based o
 
 See [Upgrade Guide](https://redash.io/help/open-source/admin-guide/how-to-upgrade).
 
+### How do I backup my PostgreSQL database?
+
+```
+# docker compose -f /opt/redash/compose.yaml exec -T postgres pg_dumpall -U postgres > backup-$(date +%Y%m%d).sql
+```
+
+### How do I upgrade PostgreSQL to a newer major version?
+
+If you are running PostgreSQL 17 or earlier and want to upgrade to PostgreSQL 18, you need to update the volume mount
+path in your `/opt/redash/compose.yaml`.  See the
+[pgautoupgrade documentation](https://github.com/pgautoupgrade/docker-pgautoupgrade#error-message-when-mounting-data-to-varlibpostgresqldata-on-postgres-v18)
+for details.
+
 ### How do I use `setup.sh` on a different operating system?
 
 You will need to create a docker installation function that suits your operating system, and maybe other functions as

data/compose.yaml

@@ -38,14 +38,22 @@ services:
     image: redis:7-alpine
     restart: unless-stopped
   postgres:
-    # [IMPORTANT]
-    # We intentionally fix the version to v17 to avoid automatic upgrade to v18 (or later).
-    # If you want to upgrade to v18, please refer to the official upgrade guide:
-    # https://github.com/pgautoupgrade/docker-pgautoupgrade#one-shot-mode
-    image: pgautoupgrade/pgautoupgrade:17-alpine
+    # pgautoupgrade can perform PostgreSQL major version upgrades when you update this image tag to a newer major version.
+    #
+    # [NOTE FOR EXISTING USERS]
+    # If upgrading from PG17 or earlier, the volume mount path has changed.
+    # Backup your data first, then stop containers and update your volume from:
+    #   /opt/redash/postgres-data:/var/lib/postgresql/data
+    # to:
+    #   /opt/redash/postgres-data:/var/lib/postgresql
+    #
+    # pgautoupgrade will automatically migrate your data to the new directory structure.
+    #
+    # Details: https://github.com/pgautoupgrade/docker-pgautoupgrade#error-message-when-mounting-data-to-varlibpostgresqldata-on-postgres-v18
+    image: pgautoupgrade/pgautoupgrade:18-alpine
     env_file: /opt/redash/env
     volumes:
-      - /opt/redash/postgres-data:/var/lib/postgresql/data
+      - /opt/redash/postgres-data:/var/lib/postgresql
     restart: unless-stopped
   nginx:
     image: redash/nginx:latest