https://adhamsalama.github.io/ A passionate backend software enginner who loves Python, TypeScript and Rust. 2026-05-08T21:42:10+00:00 Adham Salama https://adhamsalama.github.io/ Jekyll © 2026 Adham Salama /assets/img/favicons/favicon.ico /assets/img/favicons/favicon-96x96.png 2025-10-28T21:53:45+00:00 2025-10-29T22:01:17+00:00 https://adhamsalama.github.io/posts/nodejs-event-loop-based-profiling/ adham

Node.js is a single-threaded JavaScript runtime, so any CPU-intensive code will block the event loop. This is a big problem for production web servers. So how could one discover the bottleneck in their web server? Tracing Well, you could try tracing by auto-instrumenting your code using OpenTelemetry, and if the bottleneck is in any of the auto instrumented 3rd party libraries, you will have...

2025-06-08T00:00:00+00:00 2025-06-08T00:00:00+00:00 https://adhamsalama.github.io/posts/building-observability/ adham

Recently I have been working on building an obsevability platform by myself. This started when I tried to run Sentry locally and found out that it’s a bit complex to run, as it now requires: Kafka Clickhouse Snuba PostgreSQL Redis and other stuff. This probably makes sense for their scale as they have a multi-tenant platform that handles observability for several customers, but ...

2024-02-11T00:00:00+00:00 2024-02-15T21:23:47+00:00 https://adhamsalama.github.io/posts/postgres-notify-listen/ adham

I recently discovered than PostgreSQL supports alerting clients when “something” happens, kind of like a message queue, using 2 commands, NOTIFY and LISTEN. Here’s the description of the NOTIFY command from the PostgreSQL documentation. The NOTIFY command sends a notification event together with an optional “payload” string to each client application that has previously executed LISTEN cha...

2024-01-12T00:00:00+00:00 2024-01-12T00:00:00+00:00 https://adhamsalama.github.io/posts/kindle/ adham

I bought an Amazon Kindle last year and absolutely loved it; I read more tech books last year than I did in my life. I sent the some of the books to my Kindle using Amazon’s Send To Kindle app, and others using my laptop with Calibre. Send To Kindle acts like a proxy that you send the books to, then it converts the books to Amazon’s proprietary format, and saves it to your Kindle account so t...

2024-01-02T00:00:00+00:00 2024-01-02T00:00:00+00:00 https://adhamsalama.github.io/posts/kafka-zombie-messages/ adham

Kafka doesn’t neccessarily delete messages after retention time passed. I encountered this issue and it took me a couple of hours until I discovered the root cause, explained in the following article. https://dalelane.co.uk/blog/?p=3993 The summary is that Kafka stores messages in segments, and it only appends to a segment or deletes it, but doesn’t update or delete individual messages in it....