Question 1

Compare Laravel Cache Drivers: file, database, redis, and memcached.

Accepted Answer

file and database are for development and small projects, while redis and memcached are very fast in-memory stores for production that support sharing across servers and atomic locks.

Question 2

How does Cache::remember work, and how do Atomic Locks protect a server?

Accepted Answer

Cache::remember checks for the key and returns it if found; otherwise, it runs a Closure and stores the result for the specified duration. Atomic Locks ensure only one request performs an expensive operation at a time.

Question 3

How do you use Cache Tags, and which drivers support them?

Accepted Answer

They associate multiple cache keys with shared Tags so you can invalidate and flush them together with flush(); only Redis and Memcached drivers support them.

Question 4

How do you implement HTTP response caching with ETag and Last-Modified headers in Laravel?

Accepted Answer

Send an ETag calculated from a content hash and a Cache-Control header; if the client sends a matching If-None-Match, respond with 304 Not Modified without transferring the body.

Question 5

What are the main production performance commands (route:cache, view:cache, config:cache)?

Accepted Answer

They combine routes, Blade templates, and configuration files into precompiled files on disk and in memory, reducing request-processing time close to zero.

Question 6

What are the architectural risks of caching database query results, and how do you manage Invalidation?

Accepted Answer

The risk is serving inconsistent, stale data (Stale Data); manage it by including a record ID and its update time in cache keys (Cache-Busting with updated_at), or invalidate keys in Observers.

Question 7

How does the Session Driver affect the speed and performance of a Laravel application?

Accepted Answer

The file driver (default in Laravel 10 and earlier; database became the default in Laravel 11) uses disk files and slows concurrent requests. redis and memcached store sessions in memory, while cookie stores them in the browser.

Question 8

What is Redis Pipelining, and how does it reduce network latency for hundreds of commands in Laravel?

Accepted Answer

It sends tens or hundreds of Redis commands together in one network batch rather than sending each command and waiting for its response, eliminating Round-Trip Time costs.

Question 9

What is Probabilistic Early Expiration, and how does it prevent a cache stampede?

Accepted Answer

It probabilistically recalculates and refreshes cache entries in the background, with a chance that increases as expiration approaches, so a key does not suddenly disappear for every request.

Question 10

How do automatic Eloquent model caching packages (such as laravel-model-caching) work, and what are their downsides?

Accepted Answer

They intercept Eloquent queries and cache results automatically, invalidating them through model events; their downsides include complex tracking of nested relationships and high memory use.