40081826
Description
Quiz by Eladio Rocha, updated more than 1 year ago
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Created by Eladio Rocha
about 1 year ago
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Question 1
Question
What is the primary purpose of a router in a scalable database design?
Answer
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To perform joins between shards.
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To route client requests to the appropriate shard.
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To store backup configurations for shards.
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To hash keys for partitioning data.
Question 2
Question
What is a "shard" in the context of databases?
Answer
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A method of encrypting sensitive data.
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A backup server in a replica set.
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A horizontal partition of a database.
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A tool for monitoring database traffic.
Question 3
Question
What is a major advantage of sharding in database systems?
Answer
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It eliminates the need for backups.
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It increases both scalability and redundancy.
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It simplifies complex SQL queries.
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It reduces the need for a router.
Question 4
Question
What is a replica set in MongoDB?
Answer
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A set of configuration servers.
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A collection of shards distributed across regions.
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A primary server and its associated secondary servers for redundancy.
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A group of shards that handle write-heavy traffic.
Question 5
Question
How does MongoDB ensure high availability when a primary server fails?
Answer
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Traffic is rerouted to the config server.
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Secondary servers automatically elect a new primary.
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The router assigns new shards dynamically.
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The primary server is rebooted automatically.
Question 6
Question
What does "eventual consistency" mean in the context of Cassandra?
Answer
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Data is always immediately consistent across all nodes.
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Data might take time to propagate across nodes, leading to temporary inconsistencies.
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Data must be manually synchronized across nodes.
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Consistency is not guaranteed due to system failures.
Question 7
Question
What is the "celebrity problem" in sharded databases?
Answer
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High traffic on specific shards causes uneven load distribution.
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Celebrities’ data is stored differently for security reasons.
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All shards are overloaded with high read and write requests.
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Certain shards fail to replicate data efficiently.
Question 8
Question
What is re-sharding, and why is it challenging?
Answer
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Redistributing data when adding or removing shards, which requires fault-tolerant methods.
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Creating backups for new shards added to the system.
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Replicating data across all shards during traffic spikes.
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Distributing write-heavy traffic across existing shards.
Question 9
Question
What is a key advantage of using a normalized database schema?
Answer
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It minimizes storage space and simplifies updates.
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It allows faster reads with fewer database hits.
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It duplicates data for high performance.
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It eliminates the need for joins between tables.
Question 10
Question
Why might denormalized data be preferred in a NoSQL database?
Answer
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It reduces redundancy and improves update efficiency..
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It allows for single-query retrieval of all necessary data.
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It enforces strict schema rules.
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It is easier to scale horizontally.
Question 11
Question
What should you prioritize when designing a horizontally scalable database?
Answer
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Using as many joins as possible for efficiency.
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Designing around simple key-value lookups to avoid joins.
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Avoiding hash functions for data distribution.
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Relying heavily on a single primary server for consistency.
Question 12
Question
Which database systems are examples of NoSQL?
Answer
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PostgreSQL and MySQL.
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MongoDB, Cassandra, and DynamoDB.
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Oracle and SQLite.
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Redis and HBase and SQLite
Question 13
Question
In what scenarios might you choose to use normalized data over denormalized data in a NoSQL database?
Answer
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When updates are frequent and space efficiency is important.
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When scaling horizontally is a top priority.
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When high traffic requires fewer database hits.
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When you need to perform complex joins efficiently.
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