Ruby on Rails Ruby on Rails Action Mailer, Background Jobs & Caching 3

Question 1

Which method is used for low-level caching to read or compute-and-store arbitrary data in Rails?

Accepted Answer

Rails.cache.fetch

Answer

Rails.cache.fetch checks the cache for a key, and on a miss executes the provided block to generate the value, stores it, and returns the result.

Question 2

What is the default cache store in a Rails application without any explicit cache configuration?

Accepted Answer

:memory_store

Answer

Rails defaults to :memory_store, which stores cached data in a hash within the Ruby process — data is not shared between processes or persisted across restarts.

Question 3

Which Rails view helper method is used to wrap content in a fragment cache block?

Accepted Answer

cache do

Answer

The cache helper in Rails views wraps a block of ERB content, using the provided key or object to generate a cache key and store the rendered output.

Question 4

Which cache store is recommended when multiple Rails application servers need to share a single cache?

Accepted Answer

:redis_cache_store

Answer

Redis cache store uses a centralized Redis instance accessible by all application servers, making it the standard choice for multi-server deployments.

Question 5

What is 'Russian Doll caching' in the context of Rails view caching?

Accepted Answer

Nesting cache blocks where outer caches wrap inner cached fragments

Answer

Russian Doll caching nests fragment cache blocks inside one another so that when an inner fragment's cache key changes, only that fragment is re-rendered while outer fragments remain served from cache.

Ruby on Rails Practice Test

Ruby on Rails Practice Test

Ruby on Rails Ruby on Rails Action Mailer, Background Jobs & Caching 3