Airbnb System Design | Booking.com System Design | System Design Interview Question
ฝัง
- เผยแพร่เมื่อ 5 มิ.ย. 2024
- Solution for System Design Interview Question - "Design a Hotel Booking System like Airbnb"
This is being asked by a lot of companies lately like Google, Twitter, Uber, LinkedIn, Visa, etc.
Prerequisites:
How to select the right Database for a Large Scale System: • Database Design Tips |...
Architecture diagram: github.com/codekarle/system-d...
Author: / sandeep1904
If you like this video, please help us grow by sharing this video with your friends on Facebook, connections on LinkedIn and anyone who can benefit from this.
PS: This is not the real architecture of any such platform. This is my take on how I would answer that problem.
#codekarle #systemdesign #airbnbsystemdesign #system #design #interview #amazon #faang #airbnb
![ไม่ต้องมีที่ที่ให้ฉันอยู่ แต่ขอแค่มีฉันอยู่ก็พอ (Spaceless) - getsunova [SHORT FILM]](http://i.ytimg.com/vi/MuT0d_cvJkc/mqdefault.jpg)
Very nice work brother..it helped us in building our system :) gratitude
Glad that it helped :)
Which system/which company you used this in?
@@codeKarle an homestay app we soon are going to launch :) we are a startup.
That's great to know 🙂
@@codeKarle brother do you contacts you share i am from non it but deeply wanna to made it.
@@rohitkhurana7424 did your start up come out?
One of the most complete and perfect system designs tutorial I have seen. The breadth and detail is perfect as an HLD.
Great videos on system design Sandeep. Thanks!
I have one concern about the Airbnb design. You have used Kafka for multiple things and few of them don't really require or would be actually a not-so-good design.
1. Hotel onboarding: This hotel onboarding wouldn't really require an async service as I don't see this system as write-intensive. A simple sync REST API should work.
2. Booking of a room: The booking of the room by a user & removing the room from the available list should be consistent. I think here also Kafka's use should be avoided.
In both cases, immediate reflection to the other users should be handled by a write-through cache policy. Let me know your thoughts. Thank you!
One of the best system design videos I have ever seen. Hats off to you and the mechanism you told for handling the case of reserving hotel bookings
Whenever I see your videos, it feels like I'm sitting in ofc design review meeting with a senior engineer as you don't throw fancy words, really appreciate your content _/\_
Your videos are by far the best system design resources I have found on this platform. Thank you for these valuable materials!
Very nicely explained from high level to low level. Lots of concepts covered in the whole session.
Very well explanation. I liked the way everything is explained starting from overall architecture to smaller services. Looking forward for more such videos.
Definitely the best system design video I have seen! very detailed explanation of each part
Thanks!! Glad that you liked it!
A wonderful playlist to binge watch :D More power to you Sandeep :)
Glad that you liked it :)
One of the great System design videos out on youtube. Keep up the good work..
First time on your channel, it's pretty good and easily articulated. One small suggestion is to take a break for few seconds, you are not giving any stops.
I really like your unassuming way of explaining the essence of your topic. The only suggestion I make is that make it a little more relaxed and casual. I would like to see the tension fade away.
i love you man. Your videos help me a lot in my prep. Keep it up!!
Very good video and extremely simple explanation, connecting us to the internals of the real world hotel booking.
Very nice video. very thorough and provided all the necessary information in very easy to understand way. great work.
Your videos are very helpful! Please consider uploading a low level design series as well.
Very good video. Ref the last part in terms of dividing dcs by region, it may not work if a user in USA wants to book say a hotel in India. You may want to rethink this to be an active active infrastructure with multi leader replication and IP any casting for low latencies.
This channel should have millions of subscribers.. you are highly under rated. Keep doing the good work
Thanks!!
Can't get there without your support.
Do share the channel with your friends/colleagues and hopefully we'll get there :)
Excellent explanation! Thank you for this.
Amazing walk through. Thank you making this video.
Really great video : Have some doubts below
- So how are we storing available table. Are we going to store for 365 for each hotel . That will be inefficient.
- Which service will pull data from hadoop cluster? once the analysis done from hadoop cluster aren't we storing it in Analytic DB?
- Should not we store images first to s3/gcs then later cdn?
Excellent points. I had the same question. I think we shouldn't write images directly to CDN. We will store them in an object storage and CDN will cache it based on usage of the files geographically.
Thank you very much, that was enlightening, God bless you.
Superb Sandeep. I am looking for Coupon management system design. its commonly asked across companies. On internet, there is not a single design for this.
absolutely amazing explanation!! Gratitude
excellent video. very informative and useful. Thanks and kudos to Sandeep.
Awesome video, thanks for your sharing. I learned a lot from this video and others of yours
I don't understand a few points here -
1. How is the available quantity only a function of room_id. If we are accepting date range in POST /book, it should be accounted for in the schema.
2. Assuming, we have that in the schema, we should also need to have an efficient query that checks for availaibility based on these three criterias.
very clean explanation, thank you!
Your videos are really great for improving architectural concepts.
Thanks!
Glad that you liked them.
Do share these with your colleagues :)
Great video! I think you missed a point where the hotel db needs to be updated with decremented available rooms when someone books a room via booking service, to technically there should be a room--updates src talking to kafka which decrements the available rooms
@CodeKarlw I like this design, BUT:
- Using a RDBMS for performing the booking lock may not be appreciated by all interviewers: I proposed a very similar architecture in a sr backend engineer interview @ Uber and I've been rejected with the motivation "He used a RDBMS for performing the reservation lock". It would be interesting seeing an alternate implementation. (Redis lock?)
- The service crash scenario is completely absent in the design, specifically a crash of the booking service after a payment has been successfully performed but before the booking status update
- How do you maintain the datacenter database aligned? Shared kafka topic consumed by an align service?
Thank you for your work anyway!
Love it how your mic makes you sound like you're speaking from the moon. 😂 Thank you for the video.
Well explained , to the point explanation , thanks a lot !
Got a brief insight! Ty🌟
Excellent video overall.
Automatic scalability: How much is the application developer controlling it (scripts, architecture, etc) and how much is the vendor component/cloud service provider (thresholds, metrics, etc) itself doing it?
I see a component re-usage pattern. User Service, Hotel/Cab Service, Booking Service, Search Service - Elastic Search, etc across your videos. Great to see the modularity being put into action.
You talk about trade offs and justify design choices which is a good but also reinforcing about first principles of components. Much more than an interview question which reflects knowledge and experience.
Only disappointing thing is it is rendered by poor voice recording. Sigh!
Can you please create a video focusing only on the "search hotels". I am sure that will be interesting
I'm wondering how we can get quick Search results with filters like available_quality, date_range and room_classification.
Great video Sandeep. Quick tip for Product Managers looking at this - I think the first 15 minutes and then 32:20 onwards is pretty relevant.
Wanted your thoughts on something:
The safest way to interact between the booking service and the search service would be to have a single DB where locks are taken on the respective fields when a booking is made. This would guarantee that no room is double booked ever. That approach seems very very 90s and theoretical. But is there ever a case in your design that the delay between syncing the search and booking service through Kafka can cause a double booking scenario. Are there any other cons you could think about this architecture?
Thanks in advance.
Hello, we are using only one DB for booking management. There will never be a case where there would be a double booking. there can be a case where in search experience hotel is shown as available but on trying to book - it might be shows as unavailable. But this should be in only very minimal cases
This is super great. Thanks.
Your video is amazing and informative .Thanks :)
Eagerly waiting for your new videos .hope u will make it soon
Golden video❤ , Great
Thank you for a great explanation
The content is awesome, really helpful to me. Please make videos on geographic information systems like- Google Earth, Street View, Voice recognition systems like- Siri, Alexa
Ultimate video..hats off to u
Very well explained.
Just one point of discussion here from my end:
Can we create some inventory-service and keep availability there instead of booking-service, this will help in well defined boundaries and responsibilities.
Booking service should just keep the booking information and when booking is done, it can update the availability in one single distributed transaction.
Let me know if there are any challenges/problems in the above said approach.
Great explanation and elaboration on the design.
perfect video walkthrough mate!
Excellent tutorial!
Great work!! Please upload more videos
Maja agya bhai, appreciated
Great video. I have one question though. How are you generating/updating the available_rooms table? Where's that data coming from to begin with? Thanks!
That's probably from UI/App for hotel to hotel svc right?
Every video is very helpful.
Amazing video
Thanks for the detailed content
Great work there !
Amazing video, thanks a lot
Excellent design
Really nice work! Bravoooo!
Hi Sandeep, Great video Content! Cant thank you enough! Could you please also explain the cancellation scenario
Wonderful!
Simply I love it 🥰
Really helpful!
Superb explanation .. thank you for this . One question do you have more explanation on Apache Kafka and Redis as separate topics ? It will be really helpful.
Excellent
Very well explanation
Great!! well explained.Can you post video on Flight Reservation System?
Simple and Nice video. Loved it. However, it did not cover searching of hotels in a radius. It would have been helpful to see how that might have been done.
Nice explanation!
Thank you for the insightful video. Very well delivered. Question though, Where do you place users on the waiting list, who have reserved a fully booked hotel that suddenly becomes available?. Do you need a queuing system or they can be placed in the archival
This is really top notch work. Decent depth as well. Are you SDE3 or Principal?
Great video. One thing i that i found missing in this design is :
When admin of hotel adds new rooms -> there is no flows that updates rooms availability in DB of booking service
Please let me know if i i'm missing anything on this
Ready nice video detailed explanation. I'm wondering how we can get quick Search results with filters like available_quality, date_range and room_classification. Please make a video on this.
@23.07, i guess we need to mention we need to use which isolation to achieve. I guess check and set or serailizable isolation will help in race condition. Serialiazable isolation can be used with or without locks. it is better to use serializable shapshot isolation (SSI) to get the job done without using locks.
Contentful video,very nicely explained .. Basically i was looking out for scenario , where multiple people select the same hotel almost at the same time , or like how we do solve the race condition in such a huge system ..? by avoiding same booking with multiple people.
The property ISOLATION of ACID properties deals with that. So, if you set the Isolation level of a transaction (T1) to be Serializable, no other transaction would be able to write into the tables involved in the first transaction (T1). So, whichever transaction starts first, that transaction will end first. In the case of a booking scenario, let's say, T1 and T2 are two transactions booking the same room for same dates at the same time, If T1 starts first, in the Serializable mode, then T2 will have to wait until T1 completes. When T1 completes, T2 sees that there already exists a record which it is trying to book, so it will have to rollback. In that case, you send a message to the user, that someone already booked it.
Great stuff. Thank you so much. This definitely gives me more than an idea of how to go about designing. QQ. do you have a write up for this like you have for Amazon-system-design.
Amazing Video thanks for sharing this ,Can you please add Summary for all your design videos , I see you have added for a few which gives a lot of sense . Thanks Again for all the great work 👍👍👍
Thanks!!
Yeah, that is work in progress. Other summaries would be live soon in a couple of days at www.codekarle.com/
Thank you
Thank you very much for sharing your knowledge. I have a question regarding search: hotel inventory is associated with time. For example, this particular hotel does not have room now but will have room(s) in the next 2 days. How do you store data in your ElasticSearch to allow searching for rooms given the checkin, checkout time?
Nice Video. I just have a question on inventory.
So here we are keeping the hotel rooms inventory in ELK for powering search and also in the MySQL DB (available_room table) for booking service to interact with?
Thanks!
Thank you for this presentation. It is well explained.
If possible, request to add ticket booking app design like bookmyshow, please.
Thanks Sandeep ! One request, can you create one design tutorial on Rate limiting !
This is an awesome explanation.
Requesting you to please prepare one system design video for Flight Ticket booking system also.
That would be very similar to this one, just that in that scenario, instead of hotel being the primary entity, it would be a flight ticket. Rest most of the things would remain very similar to Airbnb, be it the search flow, be it the booking flow, be it the analytics.
One difference though would be the way we interact with the third parties(Airlines) and do reconciliation. We'll try and do a video on that, but that might take some time :)
Nice Explanation , I am having one doubt here , From Hotel Service Storing the data into one MYSQL Cluster, and from Booking Service Storing the Data into Another MYSQL Cluster, then How do they in sync ? I am mean Hotel Service data and booking service data in DBS.
thanks brother
Explained very well. Please make video on online pizza delivery app system design or online shopping system design.
Another way to compare database is based on hwat is your query pattern and how you can use the functionality of database.
Very nice work @codekarle. Only thing to improve is that your voice is not very audible. There is some noise.
U a System Design God
Great turotial. The one thing which I feel is missing : Once the hotel owner adds his hostel to the service, there should be some Map segment kind of thing that should happen in order to map a hotel to a place. I mean this can't be a general search like Amazon search, if a user searches for a place, how're we going to show all the hotels in that place? For me the segment approach which you showed during Maps tutorials would work best here.
That's a great suggestion. One possible solution without breaking this design is to add some tags while adding the hotel and in that service we could also suggest some tags to the owner so that if someone searches hotels near Parvati river we get this suggestion.
Thanks for the great explanation.
Question: Why do you suggest the approach of setting the boolean "isActive" to false, to delete a record rather than using the SQL delete operation?
It's generally not a good idea to delete something from the Database. If you need that information for auditing, financial reporting, or just debugging, it'll be helpful to have that information in our DB marked inactive. Additionally delete queries so have a risk of deleting something accidentally in case of bugs, so i'll always prefer to have a delete/isActive flag and filter the active records in get queries.
Thanks for sharing. I have questions:
- Is the user service is together located in Booking service?
- I guess better to have noun in the API design, e.g. booking instead of book. WDYT?
@codeKarle please make video for 'Design metric publishing system for cloud environments', for 'Design shopping cart' and for 'Design multiplayer game'. Thanks!
Thanks for the video, I do not quite understand is HotelService database will have the same data as in ES Cluster?
Thanks for the lucid explanation. I have a couple of questions:
1. How do we maintain consistency in this design. If a room has been booked, it should immediately be blocked. Using Kafka would introduce certain delay, during which another person can book the same room.
2. Can't we use MongoDB for hotel database? A hotel has complex properties, like reviews, amenities etc. Don't you think a no sql database would better fit the use case here?
we can always have hotel/room metadata in mongo db
@Sandeep : Nice discussion. Apart from concerns(which people have already pointed out), that if we connect booking and new hotel posting with kafka, the system will become near real time for search rather than real time which I see can be improved by using SQL DB only to power the search. Also, Kafka has some retention period like 7 days , so powering elastic search from Kafka rather than the SQL DB will result in inaccuracies in listing the hotel. please let me know your thoughts on that.
I think here the intention to use Elastic search is to support Fuzzy word search and for Word search Elastic Search DB is best as it optimised for that and gives results in best Time complexity. Also, we can do it with SQL DB but the point here is scalability and when more than a 1M concurrent users tries to search at same time SQL will be overloaded. Also, kafka retention period is nothing to do with elastic search it only retains events produced.
amazing explanation. Have one doubt here, why you are using redis between mysql clustes and booking management service? if we want to put recent booking details in redis then may be it would be having some TTL and user can come to see booking details later also and it would be hiting db always. could you please elaborate use case of this?
Great content but I think an important part is missing here that how the data is being created for available_rooms tabel for every date in future ? For how many days in future shall this data be there and how will it be generated ?
Thank you so much, sir! Very detailed and extremely well explained. Grateful to be learning from a talented engineer like you, free of cost here on TH-cam! _/\_
Also, if you could create videos on LLD that would be really helpful.
have cache on top of mysql and use lazy loading for EC, instead of kafka for search service