add postgresql-tips

docs/posts/postgresql-tips.md

@@ -0,0 +1,60 @@
+---
+title: "Postgresql Tips"
+date: 2025-04-30
+draft: false
+tags: ["linux", "Debian", "Postgresql", "Database", "pg_dump"]
+authors: ["trent"]
+post: 37
+---
+date: 2025-04-30
+
+## Introduction
+Sometimes you want to recreate an postgresql database on a different
+server or postgresql instance.
+And so here are some tips how to do that.
+
+
+## Backup and Restore Using Tar File
+### create a backup with `pg_dump`
+* switch to postgres user `su - postgres`
+* create backup `pg_dump -d mytestdb -F tar -f mytestdb.tar`
+* or with specific port `pg_dump -p5432 -d mytestdb -F tar -f mytestdb.tar`
+* examine contents of tar `tar -tvf mytestdb.tar`
+* alternately make a compressed backup
+* `pg_dump -d mytestdb -Fc -f mytestdb_compressed_backup`
+
+### restore with `pg_restore`
+* switch to postgres user `su - postgres`
+* start psql `psql -p5432`
+* `postgres# CREATE USER mytestuser;`
+* `postgres# \password mytestuser`
+* `postgres# CREATE DATABASE mytestdb WITH OWNER mytestuser;`
+* list users `postgres# \du`
+* list databases `postgres# \l`
+* `exit`
+* `pg_restore -p5432 -d mytestdb mytestdb.tar`
+* or `pg_restore -p5432 -d mytestdb mytestdb_compressed_backup`
+
+### verify the restored database
+* switch to postgres user `su - postgres`
+* start psql `psql -p5432`
+* change database `postgres# \c mytestdb`
+* list tables `postgres# \d` or `postgres# \dt`
+
+## Backup and Restore Schema Only
+### create a backup with `pg_dump`
+* switch to postgres user `su - postgres`
+* create backup `pg_dump --schema-only -d mytestdb -f mytestdb_schema.sql`
+* or with specific port `pg_dump -p54342 --schema-only -d mytestdb -f mytestdb_schema.sql`
+* examine sql file `less mytestdb_schema.sql`
+* note that the generated sql assigns ownership of each table, to that of the original database owner, upon creation
+
+### restore with `psql` command
+* switch to postgres user `su - postgres`
+* `psql -p5432 -d mytestdb -f mytestdb_schema.sql`
+
+### verify the restored database
+* switch to postgres user `su - postgres`
+* start psql `psql -p5432`
+* change database `postgres# \c mytestdb`
+* list tables `postgres# \d` or `postgres# \dt`

mkdocs.yml

@@ -24,6 +24,7 @@ markdown_extensions:
 nav:
   - Home:
     - Home: index.md
+    - "Postgresql Tips": posts/postgresql-tips.md
     - "Open Elevation Api Server Upgrade": posts/open-elevation-api-server-upgrade.md
     - "Wireguard on Nspawn": posts/wireguard-on-nspawn.md
     - "Sandbox IOT Network": posts/sandbox-iot-network.md
@@ -74,6 +75,7 @@ nav:
     - FreeCodeCampChallenges: https://trentspalmer.github.io/fcc-challenges/
     - DeviceLayout: https://trentpalmer.work/6a57bbe24d8244289610bf57533d6c6f/
   - Posts:
+    - "Postgresql Tips": posts/postgresql-tips.md
     - "Open Elevation Api Server Upgrade": posts/open-elevation-api-server-upgrade.md
     - "Wireguard on Nspawn": posts/wireguard-on-nspawn.md
     - "Sandbox IOT Network": posts/sandbox-iot-network.md