How tmux Parses Escape Sequences Fast
The single hottest path in tmux is not the redraw — it is the parser. Every byte that any program in any pane produces goes through tmux’s own VT parser, and a yes or a cat of a …
Performance
How PostgreSQL Speeds Up Hash Joins
A hash join is the simplest join algorithm in the database: build a hash table from the inner relation, then probe it once per outer row. There is no sort, no merge, no nested loop …
How PostgreSQL Waits for Locks
Every lock in PostgreSQL is a bet. When a backend wants a resource that somebody else has, it has to choose: burn CPU waiting, or go to sleep and let the kernel schedule somebody …
How PostgreSQL Locks Buffers Without LWLocks
Every time PostgreSQL reads a page it does two things: it pins the shared buffer that holds the page, and it takes a content lock on that buffer so that nobody rewrites the bytes …
How PostgreSQL Allocates Memory Fast
Every C program that wants to be fast needs to be fast at allocating memory. PostgreSQL allocates memory in the tightest loop imaginable: a hash join probes its hash table once per …