the removal of parking spots from min heap wont be kLog(n)... but it will be top for only 1 heap right for others it need not be the top element... finding the element will take time and so after removal heapify will run.... increasing the time

Excellent and thought provoking, I like your teaching style where you answer and give thought provoking questions.

Great system-design-of-nextflix-or-other-products video!

so I am not sure how things are concluded. is the cache going to hold counters for all of the history that ever exists? and there's two types of consumers? one that writes individual like records to DB and one that stream aggregate and update increments to the Distributed cache?

very useful video

Waste of time. This is just an ad.

Thanks for such a great video! I have a query, why are we passing time and spot type instead of just passing the ticket (which contains both) ? Is it because of principle of least privilege?

While System design you somewhere jumped into problem solving with different scenarios. I feel that is not the goal of system design.

14:40 we can not search using key-value data store for specific value. Facebook used for messenger HBase NoSql database (key-value store) then they moved to "MyRocks, Facebook’s open source database project that integrates RocksDB as a MySQL storage engine." In messenger there's clearly an option to search by phrase. Q: Can you give some comment regarding this matter ?

I'd like to see a deep dive into Session or Fanout services

For the last use case for dispatcher algorithm where the elevator is going opposite direction to passenger, how is it different from the state where the elevator is going opposite direction to which the passenger wants to go? Seems like the same state else we are more inclined to say that passenger is on floor 1 and elevator is moving to any floor which is > 1, the last state did not make much sense to me or I got it wrong.. do let me know..

Functional requirement mentioned the need to check for the max weight and number of passengers translates to the max weight.. I did not get what we would not need the passenger class in this design as the above are calculated based on passenger object attributes

can you please suggest the order in which I should go through your videos on system design

explained very well and so easily

Doubt, when we're using queues, how dispatch server knows what are all stocks that i had to initiate connection with stock exchange ? Say, User is interested in Apple, how that's being communicated to dispatch server ?

Good video , please add database selection info more like what db and why ?

I don't see how divide and conquer would help in this scenario. Most people would go from floor 1 to the floor where they live and back. Very rarely you would see people going to other floors from floor x != 1. You could have them change elevator cars midway or so, but that is quite an inconvenience (and it would be very annoying if I had to switch 3 or more cars to reach my floor from the bottom). Maybe an adaptive system based on real-time traffic would work, or maybe a division based on functional areas of the building: office floors, living floors, cafeteria/gym floors etc, but that would entail a lot of extra complexity.

This is great content. Thanks!

This is good you create curiosity what could be done to fix, what could be done to optimise.. Good teacher does not provide the exact solution they lead to that solution

Do we really need ParkingSpotNearEntrance class extending ParkingSpotAgreementStrategy?? I am bit confused on how it is going to help

such a 42.49 minutes waste of my time.... total waste.....

Watched. --

watched. --

One of the best video content sir, keep on doing it .!

Hello, thank you for the video! I wanted to ask, why do we model different types of parking spots (e.g. handicap, compact, etc.) if the assignment of cars coming in to a parking spot does not seem to consider the type of car that should match the type of parking spot?

Dont we need to consider the weight of the passenger? The total weight of passengers should be less thn threshold. I feel we need passenger object

This shows that you already know about elevator. Also there is no implementation. I would like to see requirement -> implementation. Refine requirement, refine implementation,

interns at the end🤣

Every tweet will have the tweet_like_count field. Shouldn't we add the tweet_like_count field to the existing Tweets table? What are the pros of creating a new table?

You said no need to include vehicles but is there even a need to have a parking spot object? You could just have an ints tracking the available counts. Especially since in reality people wouldn't be allocated a particular spot...if the machine says "park on the top floor at the back" but they see a person just starting to leave on the first floor near the shop entrance then they would take that one instead You said enum type is bad but the general mantra is "favour composition over inheritance" Similarly you have entry/exit terminal using inheritance but they have different methods and you'd have to cast to make use of them

Very well explained. This should be the top video for explaining how certificates and TLS works. Liking and sharing as well.

The first part was good but the algorithm part was confusing. And at no in this video did you mention about state of the elevators controlled by the people who are inside the elevator. There would be a number pad inside the elevator where people press the actual floor button. For example, 10 people get in the elevator on floor 2. One of them wants to go to floor 1 and 9 of them want to go floor 100. Essentially it has two key functions: elevator summon and passanger dispatch. You haven't attempted to make any distinction between the two at any point in this video

There are only 65,410 ports available for general use. You don't mention this when outlining the system design.

What if the counter db fails? It is not fault tolerant in that case right?

Please improve your handwriting

Why don't you use a database to write the updates from exchange. The front end servers may be stateless and just query (point read) from database.

Watched. --

best one

similar question asked in razorpay, today

Thanks for covering the breadth of the different solutions. You started with brute force and worked up to suggest some kind of an optimal solution. However, rather than telling the "WHY" part of choosing a design pattern - you are leaving it up to the viewers to interpret and decide. Would have definitely subscribed and liked your content for wholesome information and depth.

How is top down approach not following OOPs principles?

As per your design, if a new queue is created for each follower, twitter has to create billions of queues to update the messages in home time line of all the folllowers for all active users. Assume we use Kafka. Is it possible to maintain bllions of topics/queues?

I found it very useful and insightful, happy to explore whatsapp videos for any missing stuff. I am not a developer but this gives a good overview.

13:47 if you use kafka and your consumer manually commit offsets, then after consumer died zookeeper will re-arrange topics and assign the topic to another consumer. new consumer will continue from last comimted offset. considering that, we may want to put all the updates regarding the batch into single transaction, rather than do atomic updates for every tweet.

Thankyou for asking so many questions during the design. It really helps to take a pause, think and question yourself. Your system design is very clear and informative. Thankyou

It will be nice to show how the records in each db looks like in your video. It will help to digest your content.

How will you search for an element and remove it from a minheap in log(n)? I think it is not possible.

What is the lifespan/life cycle of a session? Is same sesion and session id maintained between two users for ever?

Thanks!

Let's say we are using 4 min heaps for 4 entrances to get the closest parking spot. Then we also have 4 of 5 different types of parking spots (handicap, regular, compact, large, motorcycle), then how can we fulfill that requirement? Should we keep separate heaps for types as well?