OLAP vs OLTP: When to Use a Custom Engine for Each

OLTP (transactions) and OLAP (analytics) have different access patterns. Custom engines can fit one or both—but usually for different parts of the pipeline.

High concurrency, small reads/writes, consistency, low latency. Custom engines here are usually for the hot path: session, cart, inventory, trading state. You want predictable p99 and high QPS. The rest of OLTP (billing, user accounts) often stays on a relational DB.

Bulk reads, aggregations, scans. Often batch or scheduled; latency is less critical than throughput. Custom engines for OLAP are less common unless you have a fixed schema and need to scan/aggregate faster than your warehouse allows. Many teams use a data warehouse (Snowflake, BigQuery, etc.) and only consider custom for the ingest or real-time layer feeding it.

• OLTP – Custom engine for the hot path (one or two patterns); keep SQL for the rest. • OLAP – Custom for real-time ingest or a dedicated scan/aggregation layer if the warehouse is the bottleneck. • Hybrid – Custom OLTP hot path; stream into warehouse or lake for OLAP. At Hendoi we build custom database engines (VeloxDB) for USA, Canada, and Bengaluru. Contact us for a free quote.