Memory · Data store
Instance-Local Session State
Data storeMemoryCognition & Memoryarc:InstanceLocalSessionState
Session state held in a replica's own memory, requiring session affinity so a user's requests return to the same replica.
Responsibility. Keeps a user's session state in the serving replica's memory.
Also known as: Local memory state store, Sticky-session state, LocalMemory, Local TTL context cache
Variant of Conversation State Store abstract
When to choose. Choose when latency requirements are extreme (sub-100 ms), scale is modest (tens of instances), and session recreation after instance failure is acceptable.
Relationships
is read by dependency
- Agent Controller abstract Ch4.7
is written by dependency
- Agent Controller abstract Ch4.7
alternative to variability
Design guidance
- SHOULD NOT be used where autoscaling or instance failure would lose sessions unacceptably; new instances receive no traffic until sessions form.
- SHOULD be limited to short-TTL caching with invalidation logic in hybrid designs; relying on it forces session affinity and loses context on replica failure or rolling update.
Quantitative guidance
As stated by the sources; verify before use.
- Suited to tens of instances; stateless preferred at 100+ instances (Ch1.8).
Classification
- Patterns
- Session affinity (sticky sessions)
- Quality attributes
- Performance efficiency (ISO/IEC 25010)
Sources
- Ch1.8: T. Nguyen, "Scalability and Production Deployment," in Mastering Agentic AI Systems: Guide for the NVIDIA NCP-AAI Exam, 1st ed. 2026, ch. 1.8. ISBN: 9798244538229.
- Ch4.7: T. Nguyen, "Scaling Strategies," in Mastering Agentic AI Systems: Guide for the NVIDIA NCP-AAI Exam, 1st ed. 2026, ch. 4.7. ISBN: 9798244538229.