Sign in to unlock

Get unlimited access to all questions and answers


Get lifetime access


Track progress


Save time

18 Caching interview questions and answers for software engineers

Caching is a technique that stores a copy of a given resource and serves it back when requested. Here is a list of coding interview questions on Caching to help you get ready for your next data structures interview in 2021.

  • 1.

    What is Caching?


    In computing, a cache is a high-speed data storage layer which stores a subset of data, typically transient in nature, so that future requests for that data are served up faster than is possible by accessing the data’s primary storage location. Caching allows you to efficiently reuse previously retrieved or computed data.

  • 2.

    Is Redis just a cache?


    Like a cache Redis offers:

    • in memory key-value storage

    But unlike a cash Redis:

    • Supports multiple datatypes (strings, hashes, lists, sets, sorted sets, bitmaps, and hyperloglogs)
    • It provides an ability to store cache data into physical storage (if needed).
    • Supports pub-sub model
    • Redis cache provides replication for high availability (master/slave)
    • Supports ultra-fast lua-scripts. Its execution time equals to C commands execution.
    • Can be shared across multiple instances of the application (instead of in-memory cache for each app instance)
  • 3.

    What is Resultset Caching?


    Resultset caching is storing the results of a database query along with the query in the application. Every time a web page generates a query, the applications checks whether the results are already cached, and if they are, pulls them from an in-memory data set instead. The application still has to render the page.

  • 4.

    What is Cache Invalidation?


    There are only two hard things in Computer Science: cache invalidation and naming things.

    – Phil Karlton

    HTTP caching is a solution for improving the performance of your web application. For lower load on the application and fastest response time, you want to cache content for a long period (TTL). But at the same time, you want your clients to see fresh (validate the freshness) content as soon as there is an update.

    Cache invalidation gives you the best of both worlds: you can have very long TTLs, so when content changes little, it can be served from the cache because no requests to your application are required. At the same time, when data does change, that change is reflected without delay in the web representations.

  • 5.

    What usually should be cached?


    The results for the following processes are good candidates for caching:

    • Long-running queries on databases,
    • high-latency network requests (for external APIs),
    • computation-intensive processing
  • 6.

    Name some Cache Writing Strategies


    There are two common strategies to write data in a cache:

    1. Pre-caching data, for small pieces of data, usually during the application initialization, before any request.
    2. On-demand, checking first if the requested data is in the cache (if the data is found, it is called a cache hit), using it, improving the performance of the application. Whenever the requested data has not been written to the cache (cache miss), the application will need to retrieve it from the slower source, then writing the results in the cache, thus saving time on subsequent requests for the same data.
One tip that got me hired by Google, Microsoft, and Stripe

I've worked for Microsoft, Google, Stripe, and received offers from many other companies. One thing I learned when I was interviewing myself is that standard interview tips are woefully inadequate.

Reverse Tech Interview: Questions to Stump an Interviewer

Few people want to get into an uncomfortable environment or an unprofitable company with no prospects. If you’re wondering how to get a real feel for a company during an interview, you’re welcome. I’ll give a list of questions that interviewers don’t usually expect...

How to become a programmer, move to the US, and get a dream job

Are you curious about what you need to do to earn more than $15.000 a month, drive a Tesla, live in sunny California, and work at Google, Apple, Facebook, or Amazon?

11 Reactive Systems interview questions and answers for software engineers

Reactive systems are an architectural style that allows multiple individual applications to blend into one unit, reacting to their environment, while staying aware of each other. Here is a list of coding interview questions on Reactive Systems to help you get ready for your next data struc...

. Reactive Systems
34 Microservices interview questions and answers for software engineers

Microservice architecture – a variant of the service-oriented architecture structural style – arranges an application as a collection of loosely coupled services. In a microservices architecture, services are fine-grained and the protocols are lightweight. Here is a list of coding intervie...

. Microservices
7 Layering & Middleware interview questions for developers

Middleware in the context of distributed applications is software that provides services beyond those provided by the operating system to enable the various components of a distributed system to communicate and manage data. Middleware supports and simplifies complex distributed application...

. Layering & Middleware
55 Docker interview questions and answers for software engineers

Docker is a set of platform as a service products that use OS-level virtualization to deliver software in packages called containers. Here is a list of coding interview questions on Docker to help you get ready for your next data structures interview in 2021.

. Docker
23 Databases interview questions and answers for software engineers

A database is an organized collection of data, generally stored and accessed electronically from a computer system. Where databases are more complex they are often developed using formal design and modeling techniques. Here is a list of coding interview questions on Databases to help you g...

. Databases
21 Concurrency interview questions and answers for software engineers

In computer science, concurrency is the ability of different parts or units of a program, algorithm, or problem to be executed out-of-order or in partial order, without affecting the final outcome. Here is a list of coding interview questions on Concurrency to help you get ready for your n...

. Concurrency
13 CAP Theorem interview questions and answers for software engineers

In theoretical computer science, the CAP theorem, also named Brewer's theorem after computer scientist Eric Brewer, states that it is impossible for a distributed data store to simultaneously provide more than two out of the following three guarantees: Consistency: Every read receives the ...

. CAP Theorem
Load more posts


folder icon

Access all answers

Get the inside track on what to expect in your next tech interview. We offer you a collection of high quality technical interview questions to help you prepare for your next coding interview.

graph icon

Track progress

A smart interface helps you track your progress and focus on the topics you need. You can search through questions or sort them by difficulty or type.

clock icon

Save time

Save tens of hours searching for information on hundreds of low-quality sites designed to drive traffic and make money from advertising.

Land a six-figure job at one of the top companies.

amazon logo facebook logo google logo microsoft logo uber logo
Prepare for a technical interview

Get hired with our
tech interview questions & answers