Design Uber Ola Or Lyft Type Of Systems
These platforms help user request rides and the driver picks them up from the location and drop them at the destination selected by the user.
- What are some of the required features?
- Real-time service for booking rides
- Should have the capability of assigning rides that lets the user reach the destination fast.
- Show the ETA of the driver after booking the ride and once the ride has been started, show the ETA of the vehicle arriving at the destination.
Explain Url Shortening Service Describe How You Can Shorten Any Url
URL shortening service shortens the long URL link up to one-third of the original URL size. This service is helpful in link optimisation, measuring marketing ads performance, and audience analysis. You need all functional, non-functional, and extended requirements to execute this service. Do estimation of memory, bandwidth, storage, and traffic. You need to explain the database scheme, system APIs, and other design constraints to shorten any URL using this service.
Check this detailed solution link.
How Do You Prepare For A System Design Interview
In a System Design Interview, interviewers ask the candidate to design a web-scale application. For example, they might ask you to , design YouTube, or design Uber backend.
Unlike a coding interview question, System Design Interviews are free-form discussions, and theres no right or wrong answer. Instead, the interviewer is trying to evaluate the candidates ability to hold a conversation about the different aspects of the system and assess the solution based on the requirements that might evolve during the conversation.
The best way to think about the conversation is to imagine that you and a colleague are asked to design a large-scale system, and you are hashing out the details on the whiteboard. You are understanding the requirements, scope, and constraints before proposing a solution.
So how do you design a system in an interview if you have never built one in real life? To crack your system design interview, youll need to prepare in three areas:
Each of these dimensions flows into the next.
If you dont know the fundamentals, you wont be prepared to architect a service if you dont know how to put those systems together, you wont be able to design a specific solution once youve designed large-scale systems, you can take lessons learned and integrate them into your base knowledge.
Lets look at each of these dimensions in order.
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Design An Api Rate Limiter System For Github Or Firebase Sites
API Rate Limiters limit the API calls that a service receives in a given time period for avoiding request overload. This question can start with the coding algorithm on a single machine to the distributed network.
- What are some of the Required Features?
- What is the required request count per hour or second? Let us assume that the requirement can be 10 requests per second.
- Should the limiter notify the user if the requests are blocked?
- The limiter should handle traffic suitable according to the scale.
Topics To Prepare For Systems Design Interview
The systems design interview rounds aim at testing how you break down a large problem and tackle different parts of it. So while your tech skills are important, your critical thinking is also at display during these rounds. Narrowing down the topics to prepare for such an interview is not easy.
However, based on our experience of training over 9,000 software engineers, the following are some of the key broad categories that you should consider while preparing for a systems design interview:
- Basics of systems design
- Measuring the performance of scalable systems
- MapReduce and distributed file systems
- Systems design case studies
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Prep For The System Design Interview
In addition to coding interviews, system design is a required component of the technical interview process at many tech companies.
Practice common system design interview questions and compare your results with sample solutions: discussions, code, and diagrams.
Additional topics for interview prep:
Suggested topics to review based on your interview timeline .
Q: For interviews, do I need to know everything here?
A: No, you don’t need to know everything here to prepare for the interview.
What you are asked in an interview depends on variables such as:
- How much experience you have
- What your technical background is
- What positions you are interviewing for
- Which companies you are interviewing with
More experienced candidates are generally expected to know more about system design. Architects or team leads might be expected to know more than individual contributors. Top tech companies are likely to have one or more design interview rounds.
Start broad and go deeper in a few areas. It helps to know a little about various key system design topics. Adjust the following guide based on your timeline, experience, what positions you are interviewing for, and which companies you are interviewing with.
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Facebook System Design Interview Questions
Here are some commonly asked system design interview questions at :
Other frequently asked system design interview questions include topics on concurrency , caching, database partitioning, replication, sharding, CAP theorem, networking , real-world performance , availability and reliability , data storage and data aggregation, QPS capacity or machine estimation , and byte size estimation.
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Can You Name Some Metrics For Measuring System Performance
Interviewers may ask you this question to find out if you understand the different ways to measure system performance and the importance of these monitoring techniques. When you answer, explain how these metrics help ensure a fast and efficient system.
Example:The three most common metrics used to measure a systems performance are availability, latency and throughput. These metrics help system designers measure the speed of a users experience while interacting with a system. Availability shows us how often a system responds to a user in a ratio of Uptime vs. Downtime. Latency refers to the speed at which a message is delivered in milliseconds. Finally, throughput measures the amount of data that successfully travels through a system to a user in a specified time period. Throughput is typically calculated in bits per second.
Layer 7 Load Balancing
Layer 7 load balancers look at the application layer to decide how to distribute requests. This can involve contents of the header, message, and cookies. Layer 7 load balancers terminate network traffic, reads the message, makes a load-balancing decision, then opens a connection to the selected server. For example, a layer 7 load balancer can direct video traffic to servers that host videos while directing more sensitive user billing traffic to security-hardened servers.
At the cost of flexibility, layer 4 load balancing requires less time and computing resources than Layer 7, although the performance impact can be minimal on modern commodity hardware.
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How Do You Design A Recommendation System
Recommendation systems are used for helping users identify what they want efficiently by assisting them by offering various choices and alternatives based on their history or interests.
- What are some of the Required Features?
- Discuss what kind of recommendation system is required – whether it is for movies, e-commerce websites, songs etc.
Learn How To Design Large
Learning how to design scalable systems will help you become a better engineer.
System design is a broad topic. There is a vast amount of resources scattered throughout the web on system design principles.
This repo is an organized collection of resources to help you learn how to build systems at scale.
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What Are System Design Interviews
System design interviews typically test the knowledge and design skills of professionals seeking an upper-level position in a technological field. In system design interviews, applicants answer broad questions by developing a prototype system using key components to outline a model before explaining their approach. Interviewers may also ask job candidates questions to determine their technical knowledge and experience. They are commonly used for roles like development manager, system engineer or technical program manager.
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What Is Cap Theorem
CAP theorem says that a distributed system cannot guarantee C, A and P simultaneously. It can at max provide any 2 of the 3 guarantees. Let us understand this with the help of a distributed database system.
- Consistency: This states that the data has to remain consistent after the execution of an operation in the database. For example, post database updation, all queries should retrieve the same result.
- Availability: The databases cannot have downtime and should be available and responsive always.
- Partition Tolerance: The database system should be functioning despite the communication becoming unstable.
The following image represents what databases guarantee what aspects of the CAP Theorem simultaneously. We see that RDBMS databases guarantee consistency and Availability simultaneously. Redis, MongoDB, Hbase databases guarantee Consistency and Partition Tolerance. Cassandra, CouchDB guarantees Availability and Partition Tolerance. Complete Video Tutorial.
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Load Balancer Vs Reverse Proxy
- Deploying a load balancer is useful when you have multiple servers. Often, load balancers route traffic to a set of servers serving the same function.
- Reverse proxies can be useful even with just one web server or application server, opening up the benefits described in the previous section.
- Solutions such as NGINX and HAProxy can support both layer 7 reverse proxying and load balancing.
Is It Possible To Design Vending Machines In Java
Yes, it is possible to design vending machines for products like candy, coffee, cold-drink etc., in Java. You need to design and develop Java code for executing this machine which can accept currency coins. While developing code, you need to ensure that once a person inserts a coin, they must get a product back and get a chance back.
Check this detailed solution link.
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Samples Of Product Design Interview Questions
1. How do you think a design process should begin?
2. What is more important to you, design or function?
3. Can you describe a time when your recommendation improved the design process?
4. How do you keep abreast of the latest design trends?
5. Tell me about a time when someone disagreed with you. How was this resolved?
My Personal Background In System Design
In April 2008, I joined an internal team at Microsoft working on a large-scale project building a distributed storage solution.
Amazon had launched their Simple Storage Service in 2006, and Google launched their PaaS solution Google App Engine the same month I joined the team, so we were in the early land grab of cloud computing. Less than two years later, that project was launched to the world as a new product category: Microsoft Azure.
When I joined the Azure team, I came from working on Exchange. I understood server storage and client management, but not at this scale, and certainly not distributed across the world. It required a lot of learning on the job.
Today, the lessons myself and other cloud engineers learned in those early days are codified into the System Design discipline. Now for many companies, the System Design Interview is instrumental in the developer interview process which means it is vital for landing a job and setting your career on a good trajectory.
Note: at Educative we recently published our most comprehensive System Design resource yet: Grokking Modern System Design for Software Engineers & Managers. This course covers 13 of the most common system design interview questions and teaches you how to solve them through a modular building blocks approach. Its a great resource for any engineer hoping to level up their career.
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Caching At The Object Level
See your data as an object, similar to what you do with your application code. Have your application assemble the dataset from the database into a class instance or a data structure:
- Remove the object from cache if its underlying data has changed
- Allows for asynchronous processing: workers assemble objects by consuming the latest cached object
Suggestions of what to cache:
- User graph data
System Design Interview Questions Pattern
System design interview consists of open-ended processes facilitating a creative discussion between the candidate and the interviewer. Consequently, there are no ready answers to be followed during System Design Interview. However, a typical system design question ends in designing a system based on the problem. Therefore, we have created a standard answer framework to crack each question in a systematic way.
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Most Common System Design Interview Questions
Before we get to a complete list of system design interview questions, lets take a minute to go over the five most common questions that we found in our research.
These questions come from Glassdoor interview reports by software engineers, engineering managers, and technical program managers at Amazon, Facebook, Google, and Microsoft.
Together, these five questions made up nearly 30% of the system design interview questions that we collected across these roles.
To help you prepare answers to these questions, weve included a framework that you can use to structure your thinking. For the sake of brevity, we wont be writing out entire sample answers for each question, but well be linking to full answers that you can use to check your work.
Lets get started.
Could You Create Your Own Instagram Using System Design
Yes, it is possible to use system design and create your own Instagram. We all know that Instagram is a multi-media social media platform that provides many customised image editing features and filters. We can create a system that can capture & upload pictures, edit them using filters, and tag them to increase search visibility. Check this detailed solution link or check this video link.
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How Do You Design Global File Storage And File Sharing Services Like Google Drive Dropbox Etc
- What are some of the Required Features?
- Users should be able to upload, delete, share and download files over the web.
- File updates should be synced across multiple devices.
Specific Elements Of System Design
A system has the following specific elements.
- Architecture: It defines the structure, views, and behaviour of the system
- Data: All information and data used to design the system.
- Interface: It establishes interaction with users.
- Components: Various sub-parts or module that creates systems
- Constraints or business rules: It defines the rules or limitations of the system
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What Are The Steps To Design A Twitter Clone
Twitter’s main objective is to post tweets and follow others. The most straightforward steps to designing a Twitter clone are implementing Twitter’s main features like tweets, hashtags, followers, and audio chat in the system. We can create a Twitter clone by implementing all these features into the new system. Check this video link to know more.
Caching At The Database Query Level
Whenever you query the database, hash the query as a key and store the result to the cache. This approach suffers from expiration issues:
- Hard to delete a cached result with complex queries
- If one piece of data changes such as a table cell, you need to delete all cached queries that might include the changed cell
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How Is Performance And Scalability Related To Each Other
A system is said to be scalable if there is increased performance is proportional to the resources added. Generally, performance increase in terms of scalability refers to serving more work units. But this can also mean being able to handle larger work units when datasets grow. If there is a performance problem in the application, then the system will be slow only for a single user. But if there is a scalability problem, then the system may be fast for a single user but it can get slow under heavy user load on the application.
Relational Database Management System
A relational database like SQL is a collection of data items organized in tables.
ACID is a set of properties of relational database transactions.
- Atomicity – Each transaction is all or nothing
- Consistency – Any transaction will bring the database from one valid state to another
- Isolation – Executing transactions concurrently has the same results as if the transactions were executed serially
- Durability – Once a transaction has been committed, it will remain so
There are many techniques to scale a relational database: master-slave replication, master-master replication, federation, sharding, denormalization, and SQL tuning.
Master-slave replication
The master serves reads and writes, replicating writes to one or more slaves, which serve only reads. Slaves can also replicate to additional slaves in a tree-like fashion. If the master goes offline, the system can continue to operate in read-only mode until a slave is promoted to a master or a new master is provisioned.
- Additional logic is needed to promote a slave to a master.
- See Disadvantage: replication for points related to both master-slave and master-master.
Master-master replication
Both masters serve reads and writes and coordinate with each other on writes. If either master goes down, the system can continue to operate with both reads and writes.
Disadvantage: master-master replication
Disadvantage: replication
Disadvantage: federation
Disadvantage: sharding
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