Does EF Core Query Compilation Lock Cause Latency Spikes Under Concurrent Requests?

Goal

To determine whether the internal query‑compilation lock in Entity Framework Core (EF Core) introduces unpredictable latency when multiple concurrent requests trigger new query shapes.

Constraints & Uncertainty

EF Core’s compilation cache is guarded by a per‑AppDomain lock. Under high concurrency, several threads may wait for the lock, potentially delaying the first execution of a query. Additionally, DbContext pooling, connection pooling, and default change‑tracking can interact with this contention in ways that are hard to isolate in a single‑threaded test.

Specific Questions

• Does the query‑compilation lock create measurable latency spikes when many threads request new query shapes simultaneously?
• Can pre‑compiling queries or disabling compilation caching mitigate these spikes without harming performance?
• Under what circumstances does DbContext pooling contribute to latency under concurrent load, and how does this interact with the compilation lock?