Best of 2025

The blog posts Hacker News loved most in 2025. 542 posts.

Systems & Performance
9

Jemalloc Postmortem

The jemalloc memory allocator was first conceived in early 2004, and hasbeen in public use for about 20 years now. Thanks to the nature of open source software licensing,jemalloc will remain publicly available indefinitely. But active upstream development has come to anend. This post briefly desc...

20

Jepsen: Amazon RDS for PostgreSQL 17.4

AWS’s Sergey Melnik, along with HN commenters matashii and Ants Aasma, have identified the cause of Long Fork in PostgreSQL clusters. As described a 2013 mailing list post , the order in which a PostgreSQL primary makes transactions visible is determined by an in-memory lock. Secondaries, however, make transactions…

21

Fil's Unbelievable Garbage Collector

Fil-C uses a parallel concurrent on-the-fly grey-stack Dijkstra accurate non-moving garbage collector called FUGC (Fil's Unbelievable Garbage Collector). You can find the source code for the collector itself in fugc.c , though be warned, that code cannot possibly work without lots of support logic in the rest of the…