Igeometry Podcast

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 --- Support this podcast: https://anchor.fm/hnasr/support

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

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.  --- Support this podcast: https://anchor.fm/hnasr/support

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 24:20 How Postgres 14 Addresses index bloat Cards: 14:12 b-tree https://www.youtube.com/watch?v=a1Z40OC553Y Resources https://www.postgresql.org/docs/14/btree-implementation.html#BTREE-DELETION --- Support this podcast: https://anchor.fm/hnasr/support

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. --- Support this podcast: https://anchor.fm/hnasr/support

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 --- Support this podcast: https://anchor.fm/hnasr/support

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 created by this transaction (millions in my case) are now invalid and should NOT be read by any new transaction. You have two solutions to address this, do you clean all dead rows eagerly on transaction rollback? Or do you do it lazily as a post process? Postgres does the lazy approach, a command called vacuum which is called periodically Postgres attempts to remove those dead rows and free up space in the page. Whats the harm of leaving those dead rows in? Its not really correctness issues at all, in fact transactions

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://nginx.husseinnasser.com Get my Python on the Backend course https://python.husseinnasser.com --- Support this podcast: https://anchor.fm/hnasr/support

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 Learn the fundamentals of databases, grab my my Introduction to Database Engineering udemy course here for a discount coupon https://database.husseinnasser.com

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 24:30 Best certificates are short 26:30 Summary Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

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

Quick summary of the Facebook, Instagram and WhatsApp outage on Oct 4th 2021 --- Send in a voice message: https://anchor.fm/hnasr/message Support this podcast: https://anchor.fm/hnasr/support

In this episode I discuss my recent flight through Alaskan airlines and how they block certain services but allow only texting. --- Support this podcast: https://anchor.fm/hnasr/support

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 Attack 12:00 Spook.js Extension Attack 13:00 Summary Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

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

Let us take a moment to appreciate the TCP/IP design by discussing it. --- Support this podcast: https://anchor.fm/hnasr/support

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 good about HTTP/3 37:00 What’s wrong with HTTP/3 Resources https://github.com/grpc/proposal/pull/256/files Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

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.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join

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/PAJ5kK50qp8 connect method --- Support this podcast: https://anchor.fm/hnasr/support

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 --- Support this podcast: https://anchor.fm/hnasr/support