The Backend Engineering Show with Hussein Nasser

Google linux boxes have over 16 NVMe SSD PCIe Express drives.When a shutdown signal is sent to linux, the OS iterate through each NVMe and send synchronous request to shutdown that takes 4.5 seconds. This adds up to over a minute to achieve a reboot. Google patches linux with asynchronous Shutdown APIs    Resources https://www.phoronix.com/forums/forum/phoronix/latest-phoronix-articles/1316262-google-has-a-problem-with-linux-server-reboots-too-slow-due-to-too-many-nvme-drives  patch https://lore.kernel.org/lkml/20220328230008.3587975-1-tansuresh@google.com/  Sync vs async  https://www.youtube.com/results?search_query=asynchronous+vs+synchronous+hussein

Hash tables are effective for caching, database joins, sets to check if something is in a list and even load balancing, partitioning and sharding and many other applications. Most programming languages support hash tables. However they don’t come without their cost and limitations lets discuss this. 0:00 Intro 1:50 Arrays 3:50 CPU Cost (NUMA/M1 Ultra) 6:50 Hash Tables 10:00 Hash Join 16:00 Cost of Hash Tables 20:00 Remapping Cost Hash Tables 22:30 Consistent hashing

Aggregate functions like Count, max, min, avg performance really depends on how did you tune your database for that kind of workload. Let us discuss this. 0:00 Intro 1:22 SELECT COUNT(*) 4:30 SELECT AVG(A) 5:15 SELECT MAX(A) 8:00 Best case scenario 11:30 Clustering 14:00 Clustering Sequential Writes 17:19 Clustering Random Writes 20:30 Summary

99% of phishing attacks can be avoided by looking at the URL. However this secuirty researcher proves that not enough.   https://mrd0x.com/browser-in-the-browser-phishing-attack/

On March 8 2022 Spotify and Discord experienced an outage latest 2-3 hours. The reason was a configuration on the xDS formats on Google Traffic Director. Let us discuss how this change caused the outage and what Spotify did to mitigate that outage without relying on Google restoring the service back up. Resources Spotify outage https://engineering.atspotify.com/2022/03/incident-report-spotify-outage-on-march-8/ Google Cloud outage https://status.cloud.google.com/incidents/LuGcJVjNTeC5Sb9pSJ9o Envoy xDS https://blog.envoyproxy.io/the-universal-data-plane-api-d15cec7a Microservices scaling with common sense https://www.youtube.com/watch?v=NsIeAV5aFLE CARDS 4:36 Miicros https://www.youtube.com/watch?v=NsIeAV5aFLE 9:30 Spotify Hermes https://www.youtube.com/watch?v=fMq3IpPE3TU&t=21s 0:00 Intro 2:00 Spotify Outage 3:30 Microservices 6:10 Service Discovery 10:00 Spotify Quick Workaround 12:15 Google Traffic Director Outage

The Russia-Ukraine Cyberwar has reached a peak this past week. In this video I explain the multiple ways a Denial of Service attacks can happen and how to protect against them Intro 0:00 What is DOS? 1:00 Long running requests 1:42 Crash backend processes 3:30 Exhaust Max connections 4:25 Large response (web traffic) 5:42 Lots of requests 8:27 Complex request (Regex bug) 9:57 Prevention 12:27

 Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon) https://database.husseinnasser.com Chrome, Edge and Firefox are approaching version 100. that version is 3 digit version where most websites only checked two digits. You can imagine what can go wrong. Lets discuss

On 2/22/2022 Slack experienced a 3 hours outage from 6AM to 9AM PST because of a configuration change. That change lead to increase load to their database infrastructure which causes queries to starve. Lets discuss https://status.slack.com/2022-02-22

It looks like there is demand for bringing QUIC and HTTP/3 to NodeJS, someone donated $1000 dollar to make it happen. However, what are the use cases for supporting HTTP/3 in Nodejs? I talk about whether HTTP/3 should come to NodeJS in this video. https://rysolv.com/issues/detail/863986ce-c8d5-466d-abf4-476d3177452d

Five major Canadian banks went offline for hours blocking access to online and mobile banking as well as e-transfers for customers. There are no reports of what might have caused the outage so In this video we explain what might have caused it.   https://www.bleepingcomputer.com/news/security/canadas-major-banks-go-offline-in-mysterious-hours-long-outage/