Azure Cosmos DB Flashcards

What is the 'Session' consistency level in Azure Cosmos DB?

Answer: Guarantees that a client reads its own writes within its session

Session consistency guarantees monotonic reads, monotonic writes, and read-your-own-writes within a single client session, making it ideal for single-user scenarios.

What is Azure Cosmos DB serverless mode, and when should you use it?

Answer: A consumption-based mode where you pay per RU consumed, suited for sporadic workloads

Serverless mode bills per RU consumed rather than provisioned throughput, making it cost-effective for unpredictable or low-traffic workloads.

Which conflict resolution policy in Cosmos DB multi-master automatically picks the winning write based on the highest timestamp?

Answer: Last-Write-Wins (LWW) using _ts

Last-Write-Wins uses the _ts (timestamp) property by default to automatically resolve write conflicts by selecting the item with the highest timestamp.

What is the role of a Cosmos DB trigger in server-side programming?

Answer: Executes pre-trigger or post-trigger JavaScript logic before or after item operations

Cosmos DB triggers are server-side JavaScript functions that execute either before (pre-trigger) or after (post-trigger) a document operation like create or update.

Which Cosmos DB feature allows you to query data in Azure Blob Storage or Data Lake Storage using the Cosmos DB SQL API without moving the data?

Answer: Azure Synapse Link (Analytical Store)

Azure Synapse Link with Cosmos DB analytical store enables analytical queries on Cosmos DB data from Synapse Analytics without ETL or impacting transactional performance.

In Azure Cosmos DB, what is the maximum physical partition size before Cosmos DB automatically splits it?

Answer: 20 GB

Cosmos DB automatically splits a physical partition when it exceeds 20 GB of storage, transparently redistributing data across new partitions.