HI brother. I cannot appreciate the videos enough. From last two days I am binge watching. Please upload more videos on designing the system.

A much needed concept. Thanks for this lesson. Sir please bring the part 2 quickly. And also how can we relate redis here. If you could explain a usecase with redis server.

Read through cache - Cache Server sits in front of the DB and fetches data from DB and updates the cache in case of Miss. Cache Library would mean its the application server that's interacting with the DB

Hi Shreyansh, Thank u for the wonderful video and the contributions u made so far. One question related to the second part of this video or when the Cache Eviction Policy video will be out? OR am I missing something here?

Cache-Aside Caching Strategy Data first read from cache. If present, returned immediately. If not, its fetched from DB, updates the cache and returns Pros - Control over what gets cached. Cons - Data inconsistency issues. Complexity at application layer Read Through Caching Strategy Data is read from cache. If present, returned immediately. If not, its fetched from DB by the cache server itself, updated in cache and returned Pros - Simple Cons - Less control over what gets cached Write Around Caching Strategy Data is written to the DB. Its updated in the cache, only when read operation is performed Pros - Less data inconsistency issues Cons - Cache misses since its not always updated Write Through Caching Strategy Data is written to the DB and cache in same transaction making sure Cache is always consistent with the DB Pros - Always consistent data Cons - High latency Write Back Caching Strategy Data is written to Cache and read from Cache. Its updated in DB asynchronously using a queue/scheduler Pros - Low latency Cons - Chances of data loss

Very useful video..... indeed is one of the best i have ever seen

Bhut acha video tha theory samaj m aagya but sir isko practical me kaise select krenge aur kya kya krna pdega uska bhi detail btae

Bahut Sahi Shreyansh.....Good Job

Thanks Shreyansh Sir, Loved It.....

Could you please share, or link the video that contains Part 2, cache eviction policies

Hi Shreyansh, Does the "write around" strategy effectively solve the consistency problem? Imagine this scenario: at T1, thread-A reads a record from the database. At T2, thread-B writes the latest value of that record to the database. Subsequently, at T3, thread-B invalidates the cache, signaling that the record is no longer valid. However, at T4, thread-A updates the cache with the stale value it read at T1. This raises concerns about the efficacy of the "write around" approach in ensuring consistency. Despite the cache invalidation at T3, the update at T4 reintroduces a stale value, potentially leading to data inconsistencies. Let me know your thoughts around this.

Can you please make video to implment caching technique in distributed system.

Hi Shreyansh! Just one question - In Write Around Cache we are marking the entry in cache as dirty if it is updated on DB. Do we also need a 2 phase commit in this case as in Write Through Cache? Because updating the value as dirty in cache is a necessary operation to be completed along with DB update.

Hi Shreyansh , very useful video . But can you share the sequence diagram for all the 5 caching strategies as it will help to revise whenever needed only by seeing the sequence diagrams 😀

Thanks. very informative. One question. should'nt cache take responsibility for updating database in write-through strategy?

where is caching part 2??

Thank you @Shrayansh Jain

How is Write back Cache fault tolerant, a) what if there is down time in messaging service where server can't push the message to queue? b) What if the server crashes before sending the status to queue while it has already sent a successfull response.

In write through cache we write everything in cache and the DB in a 2phase commit, meaning cache has all data that DB has. Then the cache would be heavy as well, the searchability will take more time ! Is it good only for small data scenarios? Also what's the significance of a cache if the DB and cache have same amount of data? Correct me if I am wrong but Does the presence of cache in memory and giving faster access the only pro?

Hey Shreyansh… in write around if a put/ patch request invalidate the data and same time db goes down and then get request comes so what is the use of this stale data ?

Buddy which software u have used in this for teaching ??

You're mixing TTL with TAT

which type of cache we can use in a multiplayer game where user answer the question and they earn coins and user scale is very large ?

Sir from where u learnt all these ?

👍👍

Bhai notes thora sahi se bana diya karo. Kafi ghatiya handwriting rahti hai. Baad mein padhne pe samajh nahi aata ki kya likha hai