How would you set up backups for PostgreSQL using…

Of course, I am ready to answer this question.

To create backups of PostgreSQL using only built-in mechanisms, I would employ the following approaches:

pg_dump and pg_dumpall:
- pg_dump creates a logical backup of a single database.
- pg_dumpall creates a logical backup of all databases, including system objects (roles, tablespaces).
- They generate a text file with SQL instructions for restoration or a binary archive.
- Advantage: Ease of use, flexibility in output format.
- Disadvantage: Restoring from a logical backup can take a long time for large databases. Not suitable for continuous backups (PITR).
Example of using pg_dump:
```
# Create a logical backup of the database 'mydatabase' in plain text format:
pg_dump mydatabase > mydatabase_backup.sql

# Create a logical backup of the database 'mydatabase' in custom format:
pg_dump -Fc mydatabase > mydatabase_backup.dump

# Create a logical backup of all databases:
pg_dumpall > all_databases_backup.sql
```
Continuous Archiving and Point-in-Time Recovery (PITR):
- Involves setting parameters wal_level, archive_mode, and archive_command in postgresql.conf.
- Allows continuous streaming of archived WAL files.
- For PITR, a base backup (e.g., created with pg_basebackup) and a sequence of WAL files are required.
- Advantage: Ability to restore to any point in time, minimal impact on performance during archiving.
- Disadvantage: Requires more setup and storage management for WAL files.
Example configuration in postgresql.conf:
```
# WAL archiving setup
wal_level = replica      # or higher, needed for archiving
archive_mode = on        # Enable WAL archiving
archive_command = 'cp %p /path/to/wal_archive/%f'  # Command to copy WAL files. Replace '/path/to/wal_archive/' with your storage path.
```
Example of creating a base backup with pg_basebackup:
```
# Create a base backup in '/path/to/base_backup'
pg_basebackup -D /path/to/base_backup -F t -x -v
```
Physical copies (File-level backup):
- Copying PostgreSQL data files directly (the PGDATA directory).
- Requires stopping PostgreSQL or using filesystem snapshots.
- Not suitable for hot backups without additional tools (like LVM snapshots).
- Advantage: Simple implementation for small databases with server shutdown.
- Disadvantage: Requires server shutdown, high risk of data corruption when copying on a live server without precautions.

For a reliable and efficient backup strategy, especially for production systems, I recommend combining pg_basebackup with continuous WAL archiving to ensure PITR. This allows recovery with minimal data loss and flexible restore points. Logical backups (pg_dump, pg_dumpall) can be used for individual database copies or data transfer, but are less suitable for full-scale disaster recovery.

Automating backup processes (pg_dump, pg_basebackup) requires a scheduler like cron, but the backup commands themselves are run internally by PostgreSQL.

How would you set up backups for PostgreSQL using only internal mechanisms, without external tools like vim?