Databases, Message Queues, And Caches

Question 1

What is sharding?

Answer 1

Sharding is a technique that splits large databases into smaller, more manageable components called shards. Shards can be stored across multiple computers, called nodes, and each shard runs on a separate node. Sharding is used when a dataset is too large to be stored in a single database.

Question 2

What kinds of sharding are there?

Answer 2

Vertical and horizontal

Question 3

What is memcached?

Answer 3

Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering.

Question 4

How would you invalidate a cache?

Answer 4

By deleting an entry or setting a TTL that will delete an entry once the expiration time has elapsed.

Question 5

What is TTL

Answer 5

Time to live. Is to set an expiration on an object.

Question 6

What is TTL

Answer 6

Time to live. Is to set an expiration on an object.

Question 7

What is Redis?

Answer 7

A data store often used as a message queue.

Question 8

What is Kafka?

Answer 8

A message queue with database-like durability guarantees.

Question 9

What three concerns are often the most important in software systems?

Answer 9

Reliability, scalability, maintainability