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11. Data access
Date: 2021-10-18
Status
Accepted
Context
Services can generally access data that they do not own via the Interservice Communication Pattern, the Column Schema Replication Pattern, the Replicated Caching Pattern, or the Data Domain Pattern
Decision
Data access will follow the Interservice Communication Pattern.
All the information needed to process any given event in our system is almost always included in the event itself or already cached in the service from a previous event (e.g. the Executor registry being cached in the Roster and Auction House via new/removed executor events). Therefore, there are very few occasions where access to data from other services is needed. Since the Interservice Communication Pattern is the simplest, we will go for that.
Consequences
There will be performance and fault tolerance issues when we need to access data from other services, but since does not often occur it will not have a significant effect on the system overall.