Change Data Capture with QuestDB and Debezium

QuestDB is an open-source time-series database designed for high-demand workloads, offering ultra-low latency and high ingestion throughput with a multi-tier storage engine, supporting Parquet and SQL to ensure data portability and AI readiness. The shift from ETL to ELT paradigms allows raw data to be loaded into data lakes before transformation, which suits modern streaming architectures and is facilitated by change data capture (CDC) systems like Debezium that track and act on data changes. This setup is illustrated through a reference architecture where a Java Spring application updates stock prices in PostgreSQL, and changes are captured by Debezium, streamed to Kafka, and then ingested into QuestDB using the Kafka Connect QuestDB connector for analysis. The architecture simplifies application logic by relying on PostgreSQL for ACID-compliant transactions, Kafka for reliable data delivery, and QuestDB for storing and querying historical data. The system supports real-time and historical data analysis, as visualized through Grafana dashboards, demonstrating its capability to handle complex microservice environments by leveraging time-series queries and partitioning. This approach not only improves performance but also establishes distinct service boundaries between transactional and analytical databases, with potential extensions for long-term data storage and optimization.