Choosing a Database on Zerops

Keywords

database, postgresql, mariadb, clickhouse, sql, relational, columnar, analytics, postgres, mysql, choose database, which database

TL;DR

Use PostgreSQL for everything unless you have a specific reason not to. It's the best-supported database on Zerops with full HA, read replicas, and pgBouncer.

Decision Matrix

Need	Choice	Why
General-purpose	PostgreSQL (default)	Full HA, read replicas, pgBouncer, best Zerops support
MySQL compatibility	MariaDB	MaxScale routing, async replication
Analytics / OLAP	ClickHouse	Columnar storage, ReplicatedMergeTree, 4 protocol ports

PostgreSQL (Default Choice)

• HA: 3 nodes (1 primary + 2 replicas)
• Ports: 5432 (primary), 5433 (read replicas), 6432 (external TLS via pgBouncer)
• Connection: postgresql://${user}:${password}@${hostname}:5432/${db}
• Read scaling: Use port 5433 for read-heavy workloads

MariaDB

• HA: MaxScale routing with async replication
• Port: 3306
• Connection: mysql://${user}:${password}@${hostname}:3306/${db}
• Use when: Application requires MySQL wire protocol

ClickHouse

• HA: 3 data nodes, replication factor 3
• Ports: 9000 (native), 8123 (HTTP), 9004 (MySQL), 9005 (PostgreSQL)
• Requires ReplicatedMergeTree engine in HA mode
• Use when: Analytics, time-series, OLAP workloads

Gotchas

1. HA mode is immutable: Cannot switch HA/NON_HA after creation — delete and recreate
2. No internal TLS: Use http://hostname:port internally — VPN provides encryption
3. PostgreSQL URI scheme: Some libraries need postgres:// not postgresql:// — create a custom env var

See Also

• zerops://themes/services — PostgreSQL, MariaDB, ClickHouse service cards and wiring
• zerops://decisions/choose-cache