Oracle Buffer Cache Contention Causing Latency Spikes Under Concurrent Requests

Goal

Identify whether buffer‑cache contention is responsible for intermittent latency spikes that only surface when multiple sessions issue requests concurrently. The focus is on the documented SQL_BUFFER_GET wait event and its impact on end‑to‑end response times.

Constraints & Uncertainty

Single‑threaded tests show no performance degradation, yet production workloads exhibit significant delays. The uncertainty lies in determining whether the contention is driven by buffer‑pool allocation strategy (shared, fixed, or dedicated), adaptive cursor sharing, or parallel query execution. Oracle Database versions 12c and 19c may exhibit different behavior due to changes in buffer‑cache management.

Questions

• What patterns of SQL_BUFFER_GET waits appear in V$SESSION_WAIT or V$ACTIVE_SESSION_HISTORY during peak concurrent activity?
• How does altering the buffer‑pool allocation strategy influence the frequency and duration of these waits?
• Can enabling a dedicated pool for hot tables mitigate the observed latency spikes under high concurrency?