Codemia | My Solution for Designing a Simple URL Shortening Service: A TinyURL Approach with Score: 9/10

What is the main functionality of a URL shortening service?

To take a long URL and return a shorter format of that URL.

What is a non-functional requirement for the URL shortening service?

Availability over consistency.

How many reads and writes per second does the capacity estimation suggest?

Approximately 100 reads per second and 1 write per second.

What is the estimated daily data usage based on 1 read per second?

800 MB of data every day.

What type of API is used to access the shortened URL?

A GET request API that returns a 302 on success or 404 on failure.

In the database design, what type of store is suggested for a URL shortening service?

A simple persistent key-value store.

What algorithm is mentioned for redirecting requests to application servers?

Round Robin (RR) stateless algorithm.

What caching strategy is suggested for read requests in the service architecture?

Using an in-memory cache.

What is the acceptable latency goal for redirection?

Less than 20 milliseconds.

What does the write-around cache strategy involve?

The request is written only to the database without being written to the cache.

What is a major concern when generating unique IDs for shortened URLs?

Ensuring that two opposite strings do not generate the same hash.

What does eventual consistency mean in the context of this URL shortening service?

The system does not guarantee immediate availability of the link after creation.

What is one potential failure scenario mentioned for the service?

The system can go down if there is a sudden surge of traffic from a famous person posting a URL.

What approach could be taken to mitigate high traffic caused by popular links?

Using a 'push' based approach in cache for famous users.

What trade-off is made regarding latency and consistency?

Trading off consistency for faster read latency.

What challenge is mentioned regarding the database during high traffic?

The cache might miss and redirect all requests to the database, causing slowdowns.

What is one of the future improvements suggested for the service?

Implementing a mechanism to handle thundering herd problems.

What is meant by 'lowering write latency'?

Reducing the time it takes for a write request to be processed.

What kind of data has to be checked during the hash generation?

Checking whether the generated hash is already present in the database.

What is meant by LRU in the context of caching?

Least Recently Used cache eviction policy.

What algorithm is suggested for generating hashes?

A hash algorithm that maps long URLs to shorter strings.

What does 'trading off write latency for read latency' imply?

Prioritizing fast reads, even if writes are slower.

What is a consequence of using a write-around cache?

Higher cache miss rates, impacting read performance.

In Distributed Systems, what is an SPOF?

Single Point of Failure.