The Backend Engineering Show with Hussein Nasser

By Hussein NasserTechnology

The Backend Engineering Show with Hussein Nasser episodes

March 19, 2023 All Postgres Locks Explained | A Deep Dive
Get my database engineering course https://database.husseinnasser.com

In this video I do a deep dive in all locks obtained by postgres, I learned a lot while making this video and hope you enjoy it.

0:00 Intro
2:30 What are Locks?
5:30 Overview of Postgres Locks
9:10 Table-Level Locks
11:40 ACCESS EXCLUSIVE
17:40 ACCESS SHARE
19:00 ROW SHARE
20:15 ROW EXCLUSIVE
21:15 SHARE UPDATE EXCLUSIVE
23:30 SHARE
24:50 SHARE ROW EXCLUSIVE
25:18 EXCLUSIVE
25:30 Table Lock Conflict Matrix
28:30 Row-Level Locks
30:00 FOR UPDATE
33:00 FOR NO KEY UPDATE
34:00 FOR SHARE
34:40 FOR KEY SHARE
35:10 Row Lock Conflict Matrix
39:25 Page-Level Locks
42:00 Deadlocks
46:00 Advistory Locks
47:20 Summary

https://www.postgresql.org/docs/current/explicit-locking.html

50 min
March 16, 2023 Pinterest moves to HTTP/3
Pinterest moves to HTTP/3 on all their clients and edge CDNs this year. They witnessed interesting gains but not without good lesson learned. The main one was the mismatch of alt-svc vs DNS ttls.
I cover this on the next episode of the backend engineering course.
0:00 Intro
2:00 Moving h2 to h3 through alt-svc
5:00 Why HTTP/3
6:00 HTTP/1 vs HTTP/2
9:00 TCP Head of Line blocking in HTTP/2
11:00 How HTTP/3 addresses HOL
12:15 Connection Migration
13:30 Stream level congestion control
14:10 1-RTT - 0-RTT
15:41 Pinterest challenges moving HTTP/3
19:00 Migration
21:15 Future work
22:30 Summary
article https://medium.com/pinterest-engineering/pinterest-is-now-on-http-3-608fb5581094
Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon) https://backend.husseinnasser.com
26 min
March 14, 2023 Why Loom Users got each others’ sessions on March 7th 2023
On March 7 2023, Loom users started seeing each others data as a result of cookies getting leaked from the CDN. This loom security breach is really critical. Let us discuss 0:00 Intro 1:00 Why Cookies 2:00 How this happens 5:50 What caused it? 7:30 How Loom solved it? 8:20 Reading the RCA 10:30 Remedies
15 min
March 11, 2023 How Discord Stores Trillions of Messages - A deep dive
Discord engineering goes into details of how they migrated from Cassandra to ScyllaDB, improved the performance of their reads and writes and rearchitected their backend to support the new load. It is an interesting episode lets get into it
0:00 Intro
1:50 Relational vs Distributed
7:00 The Cassandra Troubles
11:00 SnowFlake vs UUID
14:30 B+Tree
19:20 B+Tree and SSDs
25:30 LSM Trees
31:00 Hot partitions
36:00 Cassandra Garbage Collector Pauses
40:00 Changing the Architecture
45:00 The Data Services
55:00 The Migration
1:02:00 Zoned Named Spaces
1:04:00 Summary
Article here How Discord Stores Trillions of Messages
https://discord.com/blog/how-discord-stores-trillions-of-messages
1 hr 10 min
February 16, 2023 Postgres Architecture | The Backend Engineering Show
Creating a listener on the backend application that accepts connections is simple. You listen on an address-port pair, connection attempts to that address and port will get added to an accept queue; The application accepts connections from the queue and start reading the data stream sent on the connection.
However, what part of your application does the accepting and what part does the reading and what part does the execution? You can architect your application in many ways based on your use cases. I have a medium post just exploring the different options.
In this video I explore the PostgreSQL process architecture in details. Please note that the information here is derived from both the Postgres doc and code. Discussions about scalability and performance are solely based on my opinions.
0:00 Intro
1:30 Overview
3:30 Postgres MVCC
5:30 Processes vs Threads
7:40 Postmaster Process
8:00 Backend Processes
13:30 Shared Buffers
14:52 Background Workers
17:18 Auxiliary Processes
17:45 Background Writer
22:30 Checkpointer
23:40 Logger
24:06 Autovacuum Launcher and Workers
25:30 WAL Processes
28:53 Startup Process
Read full article
https://medium.com/@hnasr/postgresql-process-architecture-f21e16459907
35 min
February 13, 2023 How Alt-Svc switches HTTP/2 clients to use HTTP/3 | The Backend Engineering Show
The Alt-Svc header/frame is a capability that allows the server to adverse alternative services to the connected application available in protocols, ports or domains. It is available as a response header alt-svc and also as an HTTP/2 frame. Let us discuss this capability.
0:00 Intro
1:38 what is alt-svc?
5:30 uses of h3 in alt-svc
8:00 alt-svc header
10:00 Alt-svc header with 103 early hints
14:48 h2 altsvc frame
18:30 SVCB DNS record
21:20 Summary
Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon)
https://backend.husseinnasser.com
24 min
January 28, 2023 Your DNS queries will eventually look like this (0x20 DNS encoding)
Correction: Google is implementing the proposal originally submitted by researchers from Georgia institute of tech. I incorrectly said in the video that google is proposing this .
Google is finally implementing a proposal from 2008 by researchers from Georgia institute of technology to make DNS cache poisoning .
https://astrolavos.gatech.edu/articles/increased_dns_resistance.pdf
https://datatracker.ietf.org/doc/html/draft-vixie-dnsext-dns0x20-00
0:00 Intro
2:00 How DNS Work
5:00 DNS Cache Poisoning
14:00 gOoGLe dot CoM
16:20 ASCII 0x20 casing
18:30 Randomizing the casing with encryption
22:30 limitations of this proposal
24:00 Credits
27 min
January 24, 2023 DropBox Removed their SSDs, got 20% faster writes
https://dropbox.tech/infrastructure/increasing-magic-pocket-write-throughput-by-removing-our-ssd-cache-disks
In this episode of the backend engineering show I’ll discuss how Dropbox improved their write through put by 20% by removing all their SSDs (yes I was surprised too). DropBox uses an SSD layer as a write-back cache with SMR drives as their backend persistent storage. They changed their model to write directly to the hard drives.
0:00 Intro
2:00 Article Summary
3:00 SMR Drives
6:00 SSD Cache & WriteBack
8:00 Replacing Cache
9:30 Storage Engine Background
14:30 Why did they do it
15:00 The limitation of SSDs & Zoned Namespaces
19:30 Updating the Storage Engine
22:30 Tradeoffs
26:00 Rollout
28:00 Summary
32 min
January 05, 2023 MySQL on HTTP/3 | The Backend Engineering Show
The communication between backend applications and database systems always fascinated me. The protocols keep evolving and we are in constant search for an efficient protocol that best fit the workload of Backend-DB communication.
In this episode of the backend engineering show I go through a blog written by @PlanetScale doing an experimentation of using HTTP/3 and HTTP/2 comparing it with MySQL Binary protocol.
https://planetscale.com/blog/faster-mysql-with-http3
0:00 Intro
7:45 MySQL Binary vs HTTP
10:20 The Tests
15:00 Connection Cost + Select 1
22:00 Parallel Select
26:00 The cost of H2 and H3
38 min
December 23, 2022 How Shopify’s engineering improved writes by 50% with ULID | The Backend Engineering Show
Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon)
https://database.husseinnasser.com
Shopify posted a blog on tips to for scalable payment system, one tip peeked my interest related to switching from UUID to ULID. I explore the reasoning behind this in this video.
https://shopify.engineering/building-resilient-payment-systems
0:00 Intro
1:30 idempotency
6:30 UUID vs ULID
9:50 Clustered Index
13:30 Why UUID4 Inserts are slow
17:15 How ULID helps Shopify
22:00 Problem with tail pages
25:00 Does ULID help in all cases?
Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon)
https://backend.husseinnasser.com
33 min

About The Backend Engineering Show with Hussein Nasser

From the publisher's feed

Welcome to the Backend Engineering Show podcast with your host Hussein Nasser. If you like software engineering you’ve come to the right place. I discuss all sorts of software engineering technologies and news with specific focus on the backend. All opinions are my own.