NoSQL and database choice interview questions
Document, key-value, wide-column, search, time-series and graph stores, JSONB in PostgreSQL, and how to choose.
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Questions
- Document store or relational database?Pick the fix
- JSONB in PostgreSQLPredict
- Partition keys in DynamoDB-style storesPick the fix
- Wide-column stores like CassandraPick the fix
- Search with Elasticsearch or OpenSearchPredict
- Storing time-series dataPredict
- When a graph database helpsPredict
- Embedding vs referencing in MongoDBPick the fix
- Choosing a database for a new serviceOrder the steps
- Object storage for filesPick the fix
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Flashcards · 16
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Quick quiz · 10 questions
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Mock interview · 2 sets
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Quick facts
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MongoDB document limit
16 MB per document.
S3 durability
Amazon S3 is designed for 99.999999999% (11 nines) durability.
S3 consistency
Strong read-after-write consistency for all objects since December 2020.
jsonb vs json
jsonb is stored parsed and indexable; json keeps the exact text, key order and duplicates.
Recursive CTE cycles
PostgreSQL 14 added the CYCLE clause to detect cycles in WITH RECURSIVE.
Points per day
One reading every 10 s is 8,640 a day per device.
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Sources: Topic outline informed by System Design Primer by Donne Martin and the Zalando RESTful API Guidelines, both licensed under CC BY 4.0. Every question and answer is written by Best Latest Apps. Credits and license