🗄️ Database
Read Replicas
Configure read replicas for database scaling.
Overview
Read replicas offload read queries from the primary database, improving performance for read-heavy workloads.
Diagram source
graph LR
API[API Write Requests] --> Primary[(Primary DB)]
API2[API Read Requests] --> Replica[(Read Replica)]
Primary -->|Replication| ReplicaPostgreSQL Streaming Replication
Primary Configuration
# postgresql.conf
wal_level = replica
max_wal_senders = 5
wal_keep_size = '1GB'Replica Configuration
# Create replica from primary
pg_basebackup -h primary-host -D /var/lib/postgresql/data -U replication -P
# recovery.conf (or standby.signal in PG12+)
primary_conninfo = 'host=primary-host port=5432 user=replication password=secret'TypeORM Configuration
// ormconfig.ts
{
type: 'postgres',
replication: {
master: {
host: process.env.DB_HOST,
port: 5432,
username: process.env.DB_USER,
password: process.env.DB_PASS,
database: process.env.DB_NAME,
},
slaves: [
{
host: process.env.DB_REPLICA_HOST,
port: 5432,
username: process.env.DB_USER,
password: process.env.DB_PASS,
database: process.env.DB_NAME,
},
],
},
}Query Routing
TypeORM automatically routes:
- Writes (INSERT, UPDATE, DELETE) → Primary
- Reads (SELECT) → Replicas (round-robin)
Related Pages
- Connection Pooling — pool config
- Indexing Strategy — query performance
- Auto-Scaling — scaling