Planner
CAP theorem
- Consistency
(all nodes see the same data at the same time) - Availability
(a guarantee that every request receives a response about whether it was successful or failed) - Partition tolerance
(the system continues to operate despite arbitrary message loss or failure of part of the system)
Two design philosophies at opposite ends of the consistency-availability spectrum
BASE (Basically Available, Soft state, Eventual consistency)
ACID (Atomicity, Consistency, Isolation, Durability)
How to store device updates?
End devices send heartbeats periodically to the center.
Save all heartbeats in log style.
or
Save all heartbeats in per-device documents.
... depends on HOW TO USE.
Ad-hoc Query
Explicit information
Detail of an entity
Example
Driving history
Analytic/Batch Process
Implicit information
Area trends
Example
Find communication dark zone
Road surface deterioration monitoring
Endpoints for
User/Admin Ad-hoc Query
Low latency, indexed search.
Interfaces for
Analytic/Batch Process
High throughput, sequential scan.
Our Choice in CAP theorem
High availability
Partition tolerance
Planner
By Asser Chiu
Planner
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