PostgreSQL's inet and cidr Implementation in C: One Value, Two Policies
inet and cidr share one 18-byte struct with the mask length stored inside the value; the whole difference between a host address and a network is one input check.
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PostgreSQL Skip Scans B-Tree Indexes: Reading a Non-Leading Column
PostgreSQL 18’s skip scan lets an index on (a, b) answer a query on b alone by procedurally generating the possible a values at scan time.
tmux Stores Grid Cells in Five Bytes
tmux splits a grid cell into two representations: a fat 32-byte in-memory form and a packed 5-byte stored form.
CPython's Cache of Small Integers: 1030 Immortal Objects
Every int from -5 to 1024 is allocated once at startup and marked immortal, so a = 1; b = 1; a is b is True by construction — not by accident of the language.
CPython Reuses Objects with Free Lists: Recycling Dead Objects for Free
Freelists turn the first word of a dead object into a linked-list pointer, so the next list, tuple, or float pops a ready-made shell instead of hitting the allocator.