Postgres SELECT DISTINCT Does Not Scale

This article highlights a hidden scaling risk in PostgreSQL: `SELECT DISTINCT` can degrade linearly with table size because it scans every matching row, even when only a few unique values are needed. For CIOs and technology leaders, the business impact is slower queues, higher latency, and unpredictable performance in core workflows, which can force architectural changes or workarounds as data volume grows. Strategically, IT teams should not assume intuitive SQL constructs will scale efficiently in Postgres and should validate query plans early for high-throughput, partitioned, or queue-based systems.