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Sensetif / sensetif-app-plugin

The Grafana Application Plugin for the Sensetif platform.
Apache License 2.0
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Timestamp in Cassandra model is causing duplication of P/S/D #16

Closed niclash closed 3 years ago

niclash commented 3 years ago

In the beginning, I wanted to have the full history of all changes right in the Cassandra row, but along the way I changed my mind, without updating the cluster key. So, now queries will get multiple results for each update.

Choice 1; Go down the route of having an EventSourcing approach to record keeping.

Choice 2; Just update records "normally" and add a "copy to another table" later, if full history is to be kept.

niclash commented 3 years ago

GutFeeling:tm: Analysis; I already have an approach that is close to CQRS. Messages are commands arriving on Kafka and different View models updates their respective tables which are each optimized for different queries. That would suggest that the Read Models should not contain the Event Source stream, which currently kind of sits in Kafka.

niclash commented 3 years ago

Conclusion; Drop the timestamps from clustering in these Read View models and revisit the history aspect later. "Copy to another table" might also not be the correct answer, but a matter of replaying selections of events from event store.

niclash commented 3 years ago

Fixed, without dropping created timestamps. But adding a deleted column, and manage that explicitly.