Oracle Database In-Memory Column Store: Architecture, Population, and Workload Tuning
Oracle Database In-Memory (DBIM) adds a columnar representation of data alongside the existing row-based buffer cache. The key architectural insight is that both formats coexist — OLTP operations continue using the row-store (buffer cache) for optimal single-row performance, while analytical scans use the column store for optimal aggregation performance. The optimizer decides which format to use per operation. The Dual-Format Architecture Traditional databases force a choice: row format for OLTP, column format for analytics. Oracle’s approach avoids this by maintaining both simultaneously: ...