Full Stack System Design Interview

How Are Performance And Scalability Related To Each Other

The ability to handle a large amount of traffic in any application is referred to as scalability, whereas performance is about testing the speed with which the application is running. The increased performance is directly proportional to the number of resources added to the system. The ability to handle larger data sets in the event of growing work makes scalability directly related to the performance of any design. Performance problems might affect just one user, whereas the system might eventually become slow in case of scalability issues due to heavy data load.

Example Question : Design Youtube

View the full answer to how to “Design YouTube” here.

“How would you design a large-scale, distributed system and video-sharing platform such as YouTube?”

Note that an interviewer asking such a question is not expecting a truly complete answer. YouTube today is obviously an incredibly complex system. Keep it simple. These system design questions are ultimately looking to see if you can:

System Design Interview Questions And Answers

System design questions are typically ambiguous to allow you the opportunity to demonstrate your qualifications. You can ask questions before you respond to help you narrow the scope, give you direction and clarify any expectations.

Here are six common questions you may be asked during your system design interview:

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State Difference Between Normalization And Denormalization

Normalization and denormalization are the two main methods of altering the structure of a database.

Common System Design Concepts For Interview Preparation

In the software engineering interview process system design round has become a standard part of the interview. The main purpose of this round is to check the ability of a candidate to build a complex and large-scale system. Due to the lack of experience in building a large-scale system a lot of engineers struggle with this round. There is no accurate and standard answer to the design problems. You may have different conversations with different interviewers for the same question. Due to the open-ended nature of this round, not just junior and mid-level developers but also experienced developers feel uncomfortable in this round.

This round is not much focused on coding. The interviewer wants to know how you architect the entire system and how you glue them together. If you are preparing yourself for this round then we recommend you to read the blog How to Crack System Design Round in Interviews. You should know some important system design concepts round before you jump into preparing yourself for some specific question. We are going to cover some basic concepts of system design fundamentals code to build a strong foundation for the problems in this round.

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What Are The Various Consistency Patterns Available In System Design

Consistency from the CAP theorem states that every read request should get the most recently written data. When there are multiple data copies available, there arises a problem of synchronizing them so that the clients get fresh data consistently. Following are the consistency patterns available:

• Weak consistency: After a data write, the read request may or may not be able to get the new data. This type of consistency works well in real-time use cases like VoIP, video chat, real-time multiplayer games etc. For example, when we are on a phone call, if we lose network for a few seconds, then we lose information about what was spoken during that time.
• Eventual consistency: Post data write, the reads will eventually see the latest data within milliseconds. Here, the data is replicated asynchronously. These are seen in DNS and email systems. This works well in highly available systems.
• Strong consistency: After a data write, the subsequent reads will see the latest data. Here, the data is replicated synchronously. This is seen in RDBMS and file systems and are suitable in systems requiring transactions of data.

What Are The Different Methods Of Session Management In Servlet

A session is a conversational state between client and server and it can consist of multiple requests and responses between client and server. Therefore, HTTP and web server both are stateless, the only way to maintain a session is when some unique information about the session is passed between server and client in every request and response. We can use the following methods to maintain the session:

• User Authentication

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What Is A Connection Leak In Java And How Can We Fix It

In Java, a connection leak is a situation when the developer forgets to close the JDBC connection, it is known as connection leak. The most common type of Connection Leak experienced in Java development, is when using a Connection Pool . We can fix it by closing the connection and giving special attention to the error handling code.

What Is Required To Design A Garbage Collection System

Garbage collection ensures a Java system is running appropriately and frees a programmer from having to do it manually. Hiring managers look to see if you know how to truly design the ins and outs of various systems. A GC makes systems memory efficient.

Example:”One of my recent clients needed a way to have more memory, but there was an issue with always having to go in and deal with memory deallocation. The nature behind garbage collection is to make a system appear as if it has a seemingly endless amount of memory. What is really happening is that the system is re-purposing the memory. When a system is running slowly, a garbage collector goes in and collects what is no longer being used. I set up their system so that if an object is referenced or recursive in nature, it remains. Next, it goes through methodically and marks whatever has not been referenced and sweeps only that. Using the mark and sweep method with the void command helps to repurpose and open up memory no longer being used. With this in place, my client had a faster system with less maintenance required.”

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A Lack Of Resources For Frontenders

The frontend system design interview shares many similarities with the traditional backend system design interview, specifically in how they are structured.

While many great resources focus on the backend domain, there seem to be few resources that go into depth on how to approach frontend system design interviews. In particular, resources are grounded in what companies look for in candidates.

These are the attributes that go beyond the current frontend technology trends. And make you an effective engineer in whatever tech stack you use. Understanding how to demonstrate these attributes can go a long way when practicing and preparing for the frontend system design interview.

Client Side Components Architecture

Most likely we can assume you’ll be using React for your front end system design architecture.

React is considered to be a library and not a framework, as is equivalent to the View in MVC.

Is also common to use a pattern where you just use React, and have some of the parent components be responsible for fetching the data from the backend.

Possibly with react router, if it’s a the SPA that requires multiple view.

None the less, being able to mention other front end architecture patterns might be a good to know. eg MVC, MVVM, MVP.

As well as other libraries and frameworks you might be familiar with, such as backboneJs, Vue, Angular, Ember, Rails, Django etc… if appropriate. In the context of trade off vs current choice.Or NextJS.

As well as potentially Redux and/or the concept of immutable state. or useReducer in react hooks.

Artifacts

• Mostly considerations and things you might mention and potentially use in the next two sections 5.1 and 5.2.
• Potentially use to add to the overall diagram.

• Visually identify components on the page
• Presentational and Container Component
• Mention whether you’d need a design system

Artefacts

• If an isolated component, eg a widget than just zoom in on it
• otherwise pages/views, eg design YoutTube, Instagram, Twitter etc..

• Thinking in React
• Container/Component Architecture
• Think about the user flow

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What Companies Are Looking For In A Candidate During A System Design Interview Round

Companies dont expect us to be an expert in system design. The design discussions are open-ended, there is no perfect answer to a solution, no silver bullet, there are always trade-offs involved.

They want to gauge our thought process, they want to understand how we approach a design problem or do we immediately shift into panic mode when given a problem that weve never seen before.

In my system design course Design Modern Web-Scale Distributed Applications Like a Pro besides discussing how to design large-scale services in detail Ive also discussed how to deal with a system design problem youve never seen before.

Getting back to our discussion on system design interviews. The problem that is given to us is intentionally underspecified. They want us to trigger a conversation and ask clarification questions on the problem like if there are any constraints, what kind of input the system has to handle, how much traffic the system should expect, traffic patterns and so on.

The interviewer as opposed to looking for a specific solution wants to see how we approach the problem as I stated above. And as we proceed with designing a system, we end up having a pretty detailed discussion with the interviewer on many different topics like scalability strategies, fitting technology, data handling strategies, design choices and so on. During the conversation, the interviewer tries to gauge the breadth and depth we have on the topic.

In Java What Is A Connection Leak How Can You Fix This

If a connection is opened and forgotten about, this is known as a “leak” since each time it occurs, a connection is no longer available for reuse. Connection leaks occur when some database requests or transactions are not closed properly or are not committed, causing the connections to be abandoned and closed permanently.

Java developers commonly experience Connection Leaks when using Connection Pools. In the case where there is a section of code that fails to close a connection properly, a connection will leak from the pool each time the section of code is executed. Eventually, if this situation continues, the pool will run out of connections, which is known as Pool Exhaustion. The application will hang once all available connections have been leaked. We can fix this by closing the connection and paying particular attention to any error handling code.

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State Difference Between Blue/green Deployment And Rolling Deployment

Today, the software is rapidly created and features are often changed based on customer needs, and then it is deployed into production. Each organization has its unique way of getting new applications into the production environment. Most organizations follow the standard deployment and release strategies such as Blue-Green and Rolling Deployment.

• Blue-Green Deployment Strategy:

A deployment strategy like this creates two separate infrastructure environments i.e., blue and green. A blue environment contains older code , while a green environment contains the latest code . There is only one live production environment at any given time.

Example: For instance, the green environment is live and is receiving all user traffic, while the clone is idle. Once a new version of an application is ready for release, it can be deployed to the blue environment for testing. As soon as the new release passes testing, application traffic is switched from green to blue. Blue then becomes the live production environment, and Green becomes idle, ready for testing the next release.

• Rolling Deployment Strategy

Using this deployment strategy, old versions of an application are completely replaced with the new versions by completely replacing the infrastructure on which they run.

How To Nail Your Next Tech Interview

System design interview questions are a critical part of Full Stack interviews. Top tech companies, including FAANG, use system design interview questions to gauge your understanding of and proficiency in building highly scalable systems.

This article, outlines the best strategy to answer system design interview questions at a full stack engineering interview.

If you are preparing for a full stack interview, the insights from this article will help you in understanding the aspects of technical conversation that occur during the system design round. You will also know what interviewers expect from a senior engineer in interview settings, which will help you prepare for such challenges.

Weâll do this with the help of a sample interview. Hereâs what weâll cover:

• Full Stack System Design Sample Interview Questions and Answers â Design an Events Website

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Section : Networks And Protocols

“Protocols” is a fancy word that has a meaning in English totally independent of computer science. It means a system of rules and regulations that govern something. A kind of “official procedure” or “official way something must be done”.

For people to connect to machines and code that communicate with each other, they need a network over which such communication can take place. But the communication also needs some rules, structure, and agreed-upon procedures.

Thus, network protocols are protocols that govern how machines and software communicate over a given network. An example of a network is our beloved world wide web.

You may have heard of the most common network protocols of the internet era – things like HTTP, TCP/IP etc. Let’s break them down into basics.

Summarize And Answer Questions

Last but not least is the final step of your system design interview answer. This concluding step will consist of, once more, reviewing the system requirements and summarizing and justifying all the design decisions you made along the way.

Be sure to thoroughly explain why you think these decisions are the most prudent regarding their tradeoffs. Don’t forget to mention possible alternatives you could have taken along with their tradeoffs.

It is likely your interviewer will also ask you questions about aspects of your design here.

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What Do You Know About Full

This might seem like a technical question, but isnt. Dont use this as an opportunity to dive into everything you know about server-side development or the rules of effective user experience design.

What recruiters actually want to know is whether you understand the broad field of full-stack development and the basic roles and responsibilities of a full-stack developer.

So start by explaining what full-stack development is. Then, describe their responsibilities, which include:

• Converting business requirements into software specifications for new development projects
• Designing user experiences and interactions for software applications
• Designing graphic assets for new software products and building wireframes
• Building backend systems like databases, servers, and version control systems
• Generating strategies for optimizing the scalability, performance, and stability of software applications

How Do You Manage Multiple Projects At The Same Time

Multitasking is an important skill for full-stack developers because your diverse skills might translate to working on multiple projects that are in different phases of the development cycle.

Here are a few ways to manage multiple projects happening simultaneously:

• Plan your work before you start
• Prioritize tasks from different projects
• Work only on one thing at a time
• Communicate with your manager if youre facing any challenges

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Section : Load Balancing

If you think about the two words, load and balance, you will start to get an intuition as to what this does in the world of computing. When a server simultaneously receives a lot of requests, it can slow down . After a point it may even fail .

You can give the server more muscle power or you can add more servers . But now you got to work out how the income requests get distributed to the various servers – which requests get routed to which servers and how to ensure they don’t get overloaded too? In other words, how do you balance and allocate the request load?

Enter load balancers. Since this article is an introduction to principles and concepts, they are, of necessity, very simplified explanations. A load balancer’s job is to sit between the client and server and work out how to distribute incoming request loads across multiple servers, so that the end user experience is consistently fast, smooth and reliable.

So load balancers are like traffic managers who direct traffic. And they do this to maintain availability and throughput.

When understanding where a load balancer is inserted in the system’s architecture, you can see that load balancers can be thought of as reverse proxies. But a load balancer can be inserted in other places too – between other exchanges – for example, between your server and your database.