The Backend Engineering Show with Hussein Nasser

Postgres 18 has been released with many exciting features such as UUIDv7, Over explain module, composite index skip scans, and the most anticipated asynchronous IO with worker and io_uring mode which I uncover in this show. Hope you enjoy it0:00 Intro1:30 Synchronous vs Asynchronous calls3:00 Synchronous IO6:30 Asynchronous IO10:00 Postgres 17 synchronous io 17:20 The challenge of Async IO in Postgres 1820:00 io_method worker23:00 io_method io_uring29:30 io_method sync 31:08 Async IO isn’t done! 31:30 Support for backend writers32:36 Improve worker io_method33:00 direct io support 37:00 Summary

Fundamentals of Operating Systems Course https://oscourse.winktls is brilliant.TLS encryption/decryption often happens in userland. While TCP lives in the kernel. With ktls, userland can hand the keys to the kernel and the kernel does crypto. When calling write, the kernel encrypts the packet and send it to the NIC.When calling read, the kernel decrypts the packet and handed it to the userspace. This mode still taxes the host’s CPU of course, so there is another mode where the kernel offloads the crypto to the NIC device! Host CPU becomes free. Incoming packets to the NIC are decrypted in device before they are DMAed to the kernel. outgoing packets are encrypted before they leave the NIC to the network.ktls still need handshake to happen in userspace. There is also enabling zerocopy in some cases (now that kernel has context) Deserves a video. So much good stuff.0:00 Intro2:00 Userspace SSL Libraries 3:00 ktls 6:00 Kernel Encrypts/Decrypts (TLS_SW)8:20 NIC offload mode (TLS_HW)10:15 NIC does it all (TLS_HW_RECORD)12:00 Write TX Example13:50 Read RX Example17:00 Zero copy (sendfile)https://docs.kernel.org/networking/tls-offload.html

If you are bored of contemporary topics of AI and need a breather, I invite you to join me to explore a mundane, fundamental and earthy topic.The CPU.A reading of my substack article https://hnasr.substack.com/p/the-beauty-of-the-cpu

This new PostgreSQL 17 feature is game changer. They know can combine IOs when performing sequential scan. Grab my database coursehttps://courses.husseinnasser.com

No technical video today, just talking about the idea of discipline and consistency.

Fundamentals of Operating Systems Course This video is an overview of how the operating system kernel does socket management and the different data structures it utilizes to achieve that.timestamps0:00 Intro1:38 Socket vs Connections7:50 SYN and Accept Queue18:56 Socket Sharding23:14 Receive and Send buffers27:00 Summary

Discover the fascinating world of long polling and its role in backend efficiency. Explore how it improves upon traditional polling, reducing latency and resource consumption. Delve into its benefits for scalable database management, emphasizing efficient data sorting and predictable system behavior. Learn about request resumption and how to harness the full potential of long polling to enhance your applications. This insightful discussion uncovers the genius behind a seemingly simple yet powerful design pattern.

Explore the six stages of becoming a better software engineer. Discover how deep understanding transforms your relationship with technology. Learn the art of articulating technical concepts without jargon. Delve into the emotional journey of facing inherent limitations in technology. Gain insights into software efficiency through the lens of operating systems. Ultimately, appreciate the beauty in both the flaws and strengths of technology as you navigate your path in engineering.

A new Linux kernel patch promises to enhance network performance by implementing zero-copy techniques. Instead of the traditional method, this update turns data reading into a notification process, allowing userspace to directly access the data's location. The conversation dives into the intricacies of memory management and how this innovation could revolutionize data transmission efficiency in operating systems. Curious about its impact on performance? They break down the benefits and implications of this groundbreaking approach.

Discover how Cloudflare revolutionized its CDN caching with a global cache purge that executes in under 150 ms. The shift from a centralized lazy purge to a decentralized active system showcases remarkable engineering feats. Explore the intricacies of RockDB, peer-to-peer data structures, and how these innovations address previous limitations. Delve into the performance implications of LSM versus BTree and unpack the benefits of immediate purge requests. This deep dive reveals the complexities and clever strategies behind cutting-edge backend engineering.