Pagination patterns (cursor, offset) in HLD - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Offset Pagination Limitations

Which of the following is a common drawback of using offset-based pagination in large datasets?

A It cannot be used with relational databases.

B It requires storing a cursor token on the client side.

C It can cause inconsistent results if data changes between requests.

D It always returns results faster than cursor pagination.

💡 Hint

Think about what happens if new items are added or removed while paginating.

Offset pagination uses page numbers and offsets, so if data changes between requests, the same item might appear on different pages or be skipped.

❓ Architecture

intermediate

Choosing Pagination Strategy for a Social Feed

You are designing a social media feed that updates frequently. Which pagination pattern is best to ensure users see a consistent and smooth scrolling experience?

A Cursor pagination using a unique timestamp or ID.

B Offset pagination using page numbers.

C Load all data at once without pagination.

D Random access pagination by jumping to random pages.

💡 Hint

Consider how to handle new posts appearing while the user scrolls.

Cursor pagination uses a stable cursor like a timestamp or unique ID, which helps maintain consistency even if new posts are added.

❓ scaling

advanced

Scaling Pagination for Millions of Records

When scaling a system with millions of records, which pagination method is more efficient to reduce database load and why?

A Offset pagination because it allows jumping to any page quickly.

B Cursor pagination because it loads all data into the client at once.

C Offset pagination because it caches all pages in memory.

D Cursor pagination because it uses indexed columns to fetch next items efficiently.

💡 Hint

Think about how the database uses indexes to find rows.

Cursor pagination uses indexed columns (like IDs or timestamps) to fetch the next set of rows without scanning large offsets, reducing load.

❓ tradeoff

advanced

Tradeoffs Between Cursor and Offset Pagination

Which statement best describes a tradeoff when choosing between cursor and offset pagination?

A Offset pagination is simpler but can cause inconsistent data views; cursor pagination is consistent but harder to implement.

B Cursor pagination is simpler and faster but cannot handle large datasets; offset pagination handles large datasets well.

C Offset pagination requires client to store cursor tokens; cursor pagination uses page numbers only.

D Cursor pagination always returns results in random order; offset pagination returns sorted results.

💡 Hint

Consider implementation complexity and user experience consistency.

Offset pagination is easy to implement but can show inconsistent results if data changes. Cursor pagination is more complex but provides stable views.

❓ estimation

expert

Estimating Maximum Page Number with Offset Pagination

A database table has 10 million records. If each page shows 100 records, what is the maximum page number a user can request using offset pagination?

A 10,000 pages

B 100,000 pages

C 1,000,000 pages

D 100 pages

💡 Hint

Divide total records by records per page.

10,000,000 records / 100 records per page = 100,000 pages maximum.