Real-Time Data Ingestion in ClickHouse with Spring Boot

November 17, 2025

This guide shows how to perform real-time data ingestion into ClickHouse using Spring Boot for fast analytics and dashboards.

1. Create a Real-Time Table in ClickHouse

Use MergeTree for continuous inserts.

CREATE TABLE events (
  id UInt64,
  type String,
  ts DateTime
) ENGINE = MergeTree()
ORDER BY (ts);

2. Configure Spring Boot Datasource

spring.datasource.url=jdbc:clickhouse://localhost:8123/default
spring.datasource.username=default
spring.datasource.driver-class-name=com.clickhouse.jdbc.ClickHouseDriver

3. Define Entity

@Entity
@Table(name = "events")
public class Event {
    @Id
    private Long id;
    private String type;
    private LocalDateTime ts;
}

4. Repository

public interface EventRepository extends JpaRepository<Event, Long> {}

5. Real-Time Insert Service

@Service
public class EventService {
    @Autowired private EventRepository repo;

    public void ingest(Event e) {
        repo.save(e);
    }
}

6. Streaming Inserts via REST Controller

@RestController
@RequestMapping("/events")
public class EventController {
    @Autowired private EventService service;

    @PostMapping
    public String addEvent(@RequestBody Event e) {
        service.ingest(e);
        return "OK";
    }
}

Send events with curl or any client:

curl -X POST http://localhost:8080/events -H "Content-Type: application/json" -d '{"id":1,"type":"CLICK","ts":"2025-08-25T10:00:00"}'

7. Batch Inserts for High Throughput

Use JdbcTemplate.batchUpdate for real-time streams with high volume.

jdbcTemplate.batchUpdate(
  "INSERT INTO events (id, type, ts) VALUES (?, ?, ?)",
  events,
  500,
  (ps, e) -> {
    ps.setLong(1, e.getId());
    ps.setString(2, e.getType());
    ps.setTimestamp(3, Timestamp.valueOf(e.getTs()));
  }
);