Myself

@HelloVyom The data will be stored in physical data centers in the specific locations

INTERVIEWER: WHERE DOES THE 'CLOUD' ACTUALLY STORE YOUR DATA?

@IamAroke Indexing searches the data very fastly in database , whereas cache reduces the load on the database without hitting the datbase

Backend Interview: Since indexes make queries faster, why do we still need caching?

@EOEboh TLS Handshake is missing , need to check the valid certificates and also firewall enabling for the port

The request succeeds on HTTP Fails silently on HTTPS No error in the logs No network error either What did we miss?

@astrosumitbajaj 24-04-2003 Time - around 11.45 pm Place : Somandepalli, Andhra Pradesh

Today for next 45 mins to an hour or so, you may ask question by providing your Date, time and place of birth here. Shall try my best to provide answer or give a one-liner prediction based on horoscope. Kindly Comment and RT the quoted tweet using hashtag #astrosumitbajaj #astrosumitbajaj #Astrology

@cyber_razz DOS , The attacker sends large number of systems at a time it causes disturbance in the system , to avoid this we need to use Rate limiter and captcha ...

SECURITY+ KNOWLEDGE CHECKPOINT An attacker sends a large number of requests to a server, causing it to become slow or unavailable to legitimate users. What type of attack is this? A. Phishing B. Man-in-the-Middle C. Denial-of-Service (DoS) D. Privilege escalation

@xoaanya Backend comes first ✅

As a Web Developer which comes first?? -Frontend -Backend

@mysticwillz Client → WebSocket → Kafka → Consumer → Redis → WebSocket Broadcast → Clients

You're in a software engineering interview They ask: Design a Location Tracking  application Here's how (Answer in 5 points concise thread)

@__karnati check the df -h and go to the directory and check the du -sh | sort -rh it will give the size of folders in descending order

You’re SSH’d into a server and need to quickly find the biggest files eating up disk space. What command do you run first? Ever wasted time on this in production? Share your commands below👇👇 Tag someone who’s learning Linux!

@Inosukeei_coder Due to eventual consistency or cache might not be updated

Interviewer: two users open your app. one sees updated data, the other sees old data. why?

@kritikakodes Database ✅

TECH PUZZLE: I store your data, but I’m not your code. You query me, but I don’t speak. Who am I?

@SumitM_X Refresh token will keep you stay logged in the website till it gets expired

As a developer, have you ever wondered: You open an app after months… and you are still logged in Who is keeping that session alive all this time?

@SumitM_X If we don't return any data then it will be fine to go with 204 response code , if after deletion anything needs to send as a response then we can use 200

Tech Lead tells you in API request : DELETE /users/{id} Return 204 instead of 200 after successful deletion .. What's your reply ?

@SumitM_X LIKE 'xyz%' is faster because of the prefix

Which is faster in DB: LIKE 'xyz%' or LIKE '%abc'?

@javarevisited Strong consistency ( the data will be updated synchronously used in transaction management) at a time whereas eventual consistency means asynchronous update of the data ( generally used in social media platforms)

What is the difference between: Strong Consistency vs Eventual Consistency Give a real-world example.

@suni_code They block the seats whenever a person tries to select the seats , so that other person will not select the same seat at a time

Serious question: How does BookMyShow prevent two people from booking the same seat at the same time?

@ennycodes The latency issue due to the large distance between the client and server , so checks from which server the response is coming and add the CDN (edge servers ) and add geo load balancer to route the requests to the nearest server

Interviewer: Your app loads in 1.2s locally but 5s for users in production. Same build. No errors. What’s your first move?

@_jaydeepkarale R-W conflict will occur

Two queries run concurrently: -- Transaction 1 SELECT balance FROM accounts WHERE id = 1; -- Transaction 2 UPDATE accounts SET balance = balance - 100 WHERE id = 1; Your Lead says: "No issues here." What’s your reply?

@javarevisited It returns the data of the users whose id's are not null and not equal to 10

"Interview Question: You have 100 users. 10 were referred by ID 10. 20 have a NULL referred_by_id. Query: SELECT count(*) FROM users WHERE referred_by_id != 10; What is the result? (Most people say 90. Most people are wrong.)"

@javarevisited DNS is the one who does the job ( getting the ip address using the domain name )

Interviewer: You type a URL in your browser. And the page loads. But you never typed the server’s IP address. How?

@javarevisited 2 objects will get created

90% get this wrong. How many objects are created? String s = new String("Hello"); 1? 2? 3? Explain.