In this episode of the backend engineering show, we go through a deep dive to uncover the reason behind the outage on December 7th, 2021 Amazon outage. RCA https://aws.amazon.com/message/12721 All outage analysis videos https://www.youtube.com/watch?v=dhZ5--R42AM&list=PLQnljOFTspQXdkZLiYCCh_5RBP1-T-Rnx Get the Fundamentals of Database Engineering udemy course https://database.husseinnasser.com Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join...
Dec 18, 2021•55 min
In this episode of the backend engineering show, I discuss the log4j vulnerability (CVE-2021-44228 also known as log4shell) that took the Internet by storm. 0:00 Intro 1:00 log4j 5:30 How the attack started 11:00 Attack with DNS 17:00 Remote Code Execution 23:00 Remedy 31:00 Scanning References https://nvd.nist.gov/vuln/detail/CVE-2021-44228 https://youtu.be/oC2PZB5D3Ys 🧑🏫 Courses I Teach https://husseinnasser.com/courses Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TO...
Dec 15, 2021•36 min
In this episode of the backend engineering show taken from my udemy Q&A I discuss the reasons behind Postgres HOT Optimization or heap only tuple.
Dec 03, 2021•25 min
Postgresql database implements MVCC by creating a new row version for any update/delete/or insert. While this is a sound implementation to support concurrent transactions reading old version of the rows, it does have some side effects and this is what I want to discuss in this episode of the backend engineering show. 0:00 Intro 1:00 Postgres MVCC design 6:42 MVCC on other databases 11:15 Side-effects of Row-versioning 17:00 Postgres HOT optimization 19:50 How Index bloat affects Performance 24:2...
Nov 11, 2021•28 min
Head to https://database.husseinnasser.com to get a discount coupon for my introduction to database engineering. In this video, I answer some of your questions on the Introduction to Database Engineering Course.
Nov 05, 2021•28 min
head to https://database.husseinnasser.com to get a discount coupon for my Introduction to Database Engineering course In this episode of the backend engineering show, I’ll discuss three instances where indexes can be useless and might add overhead to your operations. Let us discuss. 0:00 Intro 1:34 What is an Index? 4:00 The Cost of Indexes 6:40 Most values are the similar 13:00 WHERE UPPER(NAME)=‘RICK’ 17:10 Composite Index 23:00 How do I know if I’m using an Index...
Oct 30, 2021•27 min
The cost of a long-running update transaction that eventually failed in Postgres (or any other database for that matter. In Postgres, any DML transaction touching a row creates a new version of that row. if the row is referenced in indexes, those need to be updated with the new tuple id as well. There are exceptions with optimization such as heap only tuples (HOT) where the index doesn’t need to be updated but that doesn’t always happens. If the transaction rolls back, then the new row versions ...
Oct 21, 2021•9 min
In this episode of the backend engineering show, I’ll discuss all HTTPS/TLS binding options in Microsoft IIS and also explain why every web server and reverse proxy should have some of these fine level control. Chapters 0:00 Intro 1:00 Require Server Name Indication (SNI) 5:00 Disable TLS 1.3 Over TCP 8:30 Disable Legacy TLS 10:00 Disable OCSP Stapling 12:00 Disable QUIC 14:30 Disable HTTP/2 17:30 Certificate Get my database course https://database.husseinnasser.com Get my NGINX course https://n...
Oct 13, 2021•20 min
I get a lot of emails asking me to talk about graph databases, so I want to start researching them, but I wanted to give you guys the framework of how I think about any databases to defuse any “magic” that might be there. In this video, I discuss what constrains a database and how the use cases try to work around them. 0:00 Intro 1:50 What constrains a database? 4:00 Indexing Techniques 5:30 Storage Engines - Row-Store 9:00 Columnar Databases 12:00 Graph use cases 16:00 Graph Storage Engines Lea...
Oct 10, 2021•22 min
Certificates contain useful metadata including the public key, domain name, signature, etc. However, the private key can be leaked which causes the certificate to be invalid/dangerous to keep around. In that particular situation, we need a mechanism to revoke certificates and that is what I’m going to discuss in this show. 0:00 Intro 0:30 Why Certificates 12:00 Certificates can go bad 14:50 Certificate Revocation Lists (CRLs) 18:30 OCSP (Online Certificate Status Protocol) 20:40 OCSP Stapling 24...
Oct 08, 2021•28 min
In this episode, I go through the Facebook detailed article regarding their October 4th, 2021 outage and discuss it in length. enjoy Facebook blog: https://engineering.fb.com/2021/10/05/networking-traffic/outage-details/ 0:00 Introduction on Facebook Networking Architecture 12:00 The Cause of the Outage 17:00 What’s DNS 23:00 DNS Servers disabled BGP ads 27:00 Could the outage have been prevented? 32:00 Why did it take so long? 38:00 Why you can’t just flip everything on 41:30 Summary 🧑🏫 Cour...
Oct 06, 2021•44 min
Quick summary of the Facebook, Instagram and WhatsApp outage on Oct 4th 2021
Oct 04, 2021•8 min
In this episode I discuss my recent flight through Alaskan airlines and how they block certain services but allow only texting.
Sep 27, 2021•11 min
Spook.js is a new transient execution side channel attack which targets the Chrome web browser. We show that despite Google's attempts to mitigate Spectre by deploying Strict Site Isolation, information extraction via malicious JavaScript code is still possible in some cases. Resources https://www.spookjs.com/ https://www.chromium.org/developers/design-documents/site-isolation Paper: https://www.spookjs.com/files/spook-js.pdf Chapters 0:00 Process Isolation in Chrome 8:00 Spook.js subdomain Atta...
Sep 13, 2021•18 min
In this episode of the backend engineering show, I’ll go through the SSL Stripping attack, what caused it, what were the mitigations enforced to solve it, and why it is still a problem. 0:00 Intro 2:10 The Web Security Model 14:30 SSL Stripping Example 22:00 How to Solve SSL Stripping? 27:00 Limitations of HSTS 31:00 Summary Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🔥 Members Only Content https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oA...
Sep 06, 2021•39 min
Let us take a moment to appreciate the TCP/IP design by discussing it.
Sep 03, 2021•29 min
The gRPC team just submitted a proposal to support HTTP/3. This is big news and we have been waiting for a long time for this. In this show, I’ll discuss why would you want gRPC, why gRPC picked HTTP/2, what is actually wrong with HTTP/2 and what HTTP/3 solves. And Finally, I’ll discuss what is wrong with HTTP/3 and pitfalls that you as gRPC user might run into. Let us discuss! 0:00 Intro 1:30 why gRPC 5:20 gRPC & HTTP/2 7:30 gRPC & HTTP/3 8:50 What is wrong with HTTP/2 29:30 What is goo...
Sep 02, 2021•48 min
I discuss keepalive in TCP and HTTP and its pros and cons 0:00 Intro 3:28 What is KeepAlive 8:30 TCP KeepAlive 10:30 Middleboxes and Single-Path TCP 16:30 Middle Boxes and Keepalive 19:30 The FTP KeepAlive trap 25:00 HTTP KeepAlive 30:00 What's a good keepalive timeout? https://daniel.haxx.se/blog/2020/02/10/curl-ootw-keepalive-time/ https://datatracker.ietf.org/doc/html/rfc1122#section-4.2.3.6 https://datatracker.ietf.org/doc/html/rfc793#section-3.5 Become a Member on YouTube https://www.youtub...
Aug 29, 2021•36 min•Ep. 2
In this video I’ll illustrate how a proxy server works under the hood. I Will go through how connection establishment works without a proxy, with an HTTP proxy and finally with HTTPS proxy in tunnel mode and TLS termination mode. 0:00 Intro 1:00 Connection Establishment without a Proxy 5:00 Connection Establishment with an HTTP Proxy 15:22 Connection Establishment with an HTTPS Proxy (Tunnel mode) 19:50 Connection Establishment with an HTTPS Proxy (TLS Termination) cards 16:25 https://youtu.be/P...
Aug 23, 2021•24 min
I discuss the concept of process forking, copy on write (COW) aka shadowing, and how Redis the in-memory database take advantage of that for asynchronous snapshotting, https://redis.io/topics/persistence
Aug 21, 2021•5 min
In this episode of the backend engineering show, I discuss database clustering. This is also known as table clustering, clustered index or Index organized table all names represents the same thing. I will talk about the benefits of clustering and also the disadvantages of implementing clustering. This feature is also implicitly implemented in certain databases. More readings https://www.postgresql.org/docs/14/sql-cluster.html https://oracle-base.com/articles/8i/index-organized-tables https://doc...
Aug 20, 2021•29 min
In this video, I’ll explain synchronous vs asynchronous operations and then discuss examples where this shows up. In programming, real-time messaging, database systems, and operating systems. 0:00 Definition Synchronous vs Asynchronous 4:15 sync vs async In Programming 7:50 Sync vs Async In Real-time messaging 17:00 Sync vs Async In Database Replication 23:50 Sync vs Async in Database Commits 29:30 Sync vs Async in fsync Operating System cache Become a Member on YouTube https://www.youtube.com/c...
Aug 12, 2021•35 min
In this episode of the Backend Engineering show, I'll discuss the advanced section settings in the Application Pool in Internet Information Services in IIS. Chapters 0:00 Intro 0:30 What is an Application Pool 3:00 IIS Multi-processing 5:18 .NET CLR Version 6:00 32-bit apps 6:21 Pipeline Mode (CGI vs ISAPI vs Native) 8:45 Max Queue 10:18 CPU Limiting 16:00 Processor Affinity 20:00 Summary
Aug 09, 2021•23 min
While the benefits of partial indexes can have a great impact on your database system performance, the implications are also great if misused. Let us discuss partial indexing (Also known as filtered indexes in SQL Server) Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🔥 Members Only Content https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oAE_Eg Support my work on PayPal https://bit.ly/33ENps4 🧑🏫 Courses I Teach https://husseinnasser.com/cou...
Aug 03, 2021•19 min
Replication is the process of pushing changes from the master node to worker replica nodes in a database system to allow for horizontal scalability. One of the methods of replication is statement-based which is popular in MySQL. In this episode of the Backend Engineering Show, I explain why statement-based replication is actually a bad idea. Resources https://www.youtube.com/watch?v=jsWwFL_iqVM https://dev.mysql.com/doc/refman/8.0/en/replication-sbr-rbr.html https://engineering.fb.com/2021/07/22...
Jul 31, 2021•18 min
This episode of the backend engineering show is sponsored by my friends at RedisLabs. I’m going to break this video into three sections, we will first define features that qualify a primary database? Then we will see if Redis actually check the boxes of a primary database and finally we explore the features of Redis that take it beyond a primary database. I was personally surprised by most of those. Chapters 0:00 Intro 1:00 What Qualifies a primary database 3:00 Does Redis Check the boxes? 7:40 ...
Jul 30, 2021•13 min
There was a two hours DNS outage on a company called Akamai that broke several services today July 22, 2021, https://appleinsider.com/articles/21/07/22/akamai-dns-problem-causing-wide-internet-issues Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🔥 Members Only Content https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oAE_Eg Support my work on PayPal https://bit.ly/33ENps4 🧑🏫 Courses I Teach https://husseinnasser.com/courses...
Jul 22, 2021•55 sec
IIS (Internet Information Services) is Microsoft's Windows web server. It is feature-rich and very easy to enable. I have been using it for a long time but I noticed I never actually make a video about it. In this video, I'll explore the IIS binding and explain all the options in that form. I might make more videos in the future to explore different aspects of this web server. Videos mentioned Leaky abstractions https://youtu.be/4a3bI7AYsy4 HTTP/2 Limitations https://youtu.be/CUiBVTcgvBU OCSP St...
Jul 20, 2021•12 min
In today's show I go through the NodeJS Security Releases for the month of July 2021, lots of interesting vulnerabilities to discuss. 0:00 Intro 1:00 CVE-2021-22918 - libuv DNS Out of bounds Crash 3:40 CVE-2021-22921 - Node Windows installer Local Privilege Escalation 7:30 CVE-2021-27290 - ssri Regular Expression Denial of Service (ReDoS) Resources https://nodejs.org/en/blog/vulnerability/july-2021-security-releases/ https://hackerone.com/reports/1211160 https://snyk.io/vuln/SNYK-JS-SSRI-1085630...
Jul 09, 2021•11 min
🧑🏫 Courses I Teach https://husseinnasser.com/courses In this episode, I’d like to discuss the methods of scaling CPU-bound or intensive workloads on the backend. This show will discuss the scaling of the workload on a single machine taking full advantage effectively of all its resources, then we will discuss horizontal scalability to multiple machines. 0:00 Intro 1:00 What do I mean by Scaling 3:20 CPU-Intensive/Bound Workload 6:00 Effective Scaling CPU-Bound Backends in Single Machine 12:00 ...
Jul 05, 2021•20 min
