Sharding and partitioning in DBMS Theory - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Difference between sharding and partitioning

Which statement best describes the difference between sharding and partitioning in databases?

A Partitioning splits data across multiple machines, while sharding divides data within a single machine.

B Sharding splits data across multiple machines, while partitioning divides data within a single machine.

C Sharding and partitioning both mean the same and are used interchangeably.

D Partitioning is only used for backup purposes, while sharding is for performance.

💡 Hint

Think about whether the data is split across machines or within one machine.

Sharding means splitting data horizontally across different servers or machines to distribute load. Partitioning divides data into parts but usually within the same machine or database instance.

📋 Factual

intermediate

Common sharding key choice

Which of the following is the best choice for a sharding key in a user database?

A User's email address

B User's last login timestamp

C User's account creation date

D User's unique ID number

💡 Hint

The sharding key should evenly distribute data and be stable.

A unique ID number is stable and evenly distributed, making it a good sharding key. Email or timestamps can be uneven or change over time.

🔍 Analysis

advanced

Impact of uneven data distribution in sharding

What is the main problem caused by uneven data distribution across shards?

A The database automatically merges shards to balance data.

B Data backup becomes impossible for the overloaded shards.

C Some shards become overloaded, causing slower response times and potential failures.

D Users lose access to data stored on smaller shards.

💡 Hint

Consider what happens if one shard holds much more data than others.

When data is unevenly distributed, some shards handle more requests and data, leading to slower performance and risk of failure, while others are underused.

❓ Comparison

advanced

Horizontal vs vertical partitioning

Which statement correctly compares horizontal and vertical partitioning?

A Horizontal partitioning splits rows into groups, vertical partitioning splits columns into groups.

B Vertical partitioning splits rows into groups, horizontal partitioning splits columns into groups.

C Both horizontal and vertical partitioning split data by rows only.

D Both horizontal and vertical partitioning split data by columns only.

💡 Hint

Think about whether partitioning divides data by rows or columns.

Horizontal partitioning divides a table's rows into smaller sets. Vertical partitioning divides a table's columns into smaller sets.

❓ Reasoning

expert

Choosing sharding strategy for a global app

A global social media app wants to shard its user data to improve performance. Which sharding strategy is best to reduce latency for users worldwide?

A Shard data by user geographic region so users connect to nearby servers.

B Shard data by user age group to balance load evenly.

C Shard data by user signup date to keep recent users together.

D Shard data randomly to avoid any predictable pattern.

💡 Hint

Consider how physical location affects network speed and latency.

Sharding by geographic region places user data closer to their location, reducing network delays and improving response times.