# PostgreSQL

## Overview

PostgreSQL is the central database platform for SilverLinux.

Multiple applications use the same PostgreSQL instance while maintaining separate databases and database users.

This approach simplifies:

* Backup management
* Monitoring
* Security
* Resource utilization

---

## Service Information

Container Name:

```text
postgres
```

Network:

```text
internal
```

Purpose:

* Application databases
* Centralized data storage
* Shared database platform

---

## Current Databases

### gitea

Owner:

```text
gitea
```

Purpose:

Source control and repository management.

Used by:

```text
gitea
```

---

### openproject

Owner:

```text
openproject
```

Purpose:

Project management and collaboration.

Used by:

```text
openproject
```

---

### postgres

Owner:

```text
postgres
```

Purpose:

Administrative database.

Used for PostgreSQL administration and maintenance.

---

## Database Ownership

| Database    | Owner       |
| ----------- | ----------- |
| gitea       | gitea       |
| openproject | openproject |
| postgres    | postgres    |

Each application should use its own dedicated database user whenever possible.

---

## Credentials

Credentials are stored in:

```text
/srv/secrets/company.env
```

Current variables:

```text
POSTGRES_ROOT_PASSWORD
POSTGRES_OPENPROJECT_PASSWORD
```

Future variables:

```text
POSTGRES_GITEA_PASSWORD
POSTGRES_BAGET_PASSWORD
```

Passwords must never be committed to Git repositories.

---

## Administration

Open PostgreSQL shell:

```bash
docker exec -it postgres psql -U postgres
```

---

### List Databases

```sql
\l
```

---

### List Roles

```sql
\du
```

---

### List Connections

```sql
SELECT * FROM pg_stat_activity;
```

---

## Create Database

Example:

```sql
CREATE DATABASE myapp;
```

---

## Create User

Example:

```sql
CREATE USER myapp WITH PASSWORD 'StrongPassword';
```

Grant permissions:

```sql
GRANT ALL PRIVILEGES ON DATABASE myapp TO myapp;
```

---

## Backup

Create database backup:

```bash
docker exec postgres pg_dump -U postgres openproject > openproject.sql
```

Create full cluster backup:

```bash
docker exec postgres pg_dumpall -U postgres > postgres-full-backup.sql
```

---

## Restore

Restore database:

```bash
docker exec -i postgres psql -U postgres openproject < openproject.sql
```

Restore complete cluster:

```bash
docker exec -i postgres psql -U postgres < postgres-full-backup.sql
```

---

## Security

* PostgreSQL is not exposed publicly.
* Database traffic is restricted to Docker internal networks.
* Credentials are stored in `/srv/secrets/company.env`.
* Administrative access should use the `postgres` role only when necessary.
* Applications should use dedicated database users.

---

## Monitoring

Useful commands:

Database size:

```sql
SELECT pg_database.datname,
       pg_size_pretty(pg_database_size(pg_database.datname))
FROM pg_database;
```

Current connections:

```sql
SELECT count(*) FROM pg_stat_activity;
```

PostgreSQL version:

```sql
SELECT version();
```

---

## Disaster Recovery

Minimum requirements for recovery:

* PostgreSQL container configuration
* Database backups
* `/srv/secrets/company.env`
* Docker network configuration

Without the secrets file, applications may not be able to reconnect to their databases after restoration.

---

## Related Services

* Gitea
* OpenProject

## Related Documentation

* docs/server.md
* docs/security.md
* docs/secrets.md
* docs/backups.md