Write-Heavy Transactional Platform

Summary

A high-volume transactional write architecture anchored on PostgreSQL, where write throughput, durability guarantees, and audit completeness must coexist. The outbox pattern ensures reliable event publishing to Kafka without two-phase commit, and WAL-based CDC provides a durable change log that can reconstruct system state. Connection pooling via PgBouncer bounds connection overhead at the database layer.

Problem Statement

Payment processors, order management systems, IoT ingestion pipelines, and audit logging platforms all share the same structural problem: they must durably record every write, guarantee at-least-once event delivery downstream, and maintain strict ACID consistency: while sustaining write rates that eventually exceed what a single PostgreSQL primary can absorb. Naive synchronous dual-writes (write to DB + publish to Kafka in one transaction) create distributed consistency hazards. The outbox pattern solves this by making event publishing a side effect of the same committed transaction, consumed asynchronously by a CDC relay.