OLTP

OLTP (Online Transaction Processing) describes the class of database workloads characterised by many short-lived, latency-sensitive transactions: row-level reads and writes that back interactive applications. OLTP contrasts with OLAP (Online Analytical Processing) , where queries scan large fractions of historical data for analytics.

OLTP characteristics

• Short transactions. A few row reads and writes; complete in milliseconds.
• High concurrency. Thousands to hundreds of thousands of transactions per second.
• Row-oriented storage. Optimised for fetching whole rows quickly.
• ACID guarantees. Atomicity and isolation matter for business correctness.
• Strict latency SLAs. User-facing requests demand p99 latency targets.

OLTP vs OLAP

| OLTP| OLAP ---|---|--- Workload| Many small reads/writes| Few large scans and aggregations Storage| Row-oriented| Column-oriented Latency| Milliseconds| Seconds to minutes Examples| PostgreSQL, MySQL, DynamoDB| BigQuery, Snowflake, Redshift, ClickHouse, DuckDB

Modern HTAP (Hybrid Transactional/Analytical Processing) systems like TiDB and SingleStore aim to serve both workloads from one engine.

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Related Terms PostgreSQL, MySQL, MongoDB, ACID, MVCC, SQL.