Flashcards
Cloud - Test 1 (C)
Cards in this deck (10)
- 1Dynamo features Eventual consistency. What is it?Replicas can always accept updates. Updates are eventually propagated to all replicas. Replicas converge to the same state (after receiving the same set of updates).
- 2CosmosDB supports different database models. Which are those?1. Relational data model: Database composed by tables and documents.
2. Document data model: Document can be any JSON object.
3. Graph data model: Represent data that can be modelled as a graph (e.g. social network relations, etc.) - 3What is CosmosDB core type system?atom-record-sequence (ARS) based:
Atoms consist of a small set of primitive types e.g. string, bool, number etc
Records are structs (pairs key, value).
Sequences are arrays consisting of atoms, records or sequences. - 4What is multi-master replication?Multi-master is composed of multiple master regions that equally participate in a write-anywhere model (active-active pattern) and it is used to ensure that data is available at any time where you need it. Updates made to an individual region are asynchronously propagated to all other regions (which in turn are master regions in their own). Azure Cosmos DB regions operating as master regions in a multi-master configuration automatically work to converge the data of all replicas and ensure global consistency and data integrity.
- 5What kind of conflicts can occur during concurrent Updates?Insert conflicts: These conflicts can occur when an application simultaneously inserts two or more items with the
same unique index in two or more regions.
Replace conflicts: These conflicts can occur when an application updates the same item simultaneously in two or more regions.
Delete conflicts: These conflicts can occur when an application simultaneously deletes an item in one region and
updates it in another region - 6What conflict resolution strategies are there?1. Last-Write-Wins (LWW): uses a system-defined timestamp to select which version to keep.
2. Application-defined (Custom): possible to define a merge procedure to solve conflicts. These procedures get invoked
upon detection of the write-write conflicts – the procedure executes exactly-once - 7What is RTO and RPO?Recovery time objective (RTO) is the time until an application recover from a disruptive event.
Recovery point objective (RPO) is the period of time for which updates might get lost in a failure. - 8Replication Under the hoods
- 9Change Feed I
- 10Change Feed II
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- Flashcards on Cloud - Test 1 (C), created by Bruno Ramos on 24/10/2019.
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