IPC in PostgreSQL: Thomas Munro - PGCon 2023

Never-ending bugs 🔒

IPC (Inter-Process Communication) issues in PostgreSQL: signal handling, incorrect usage can lead to bugs 💣

latch is an unusual word in Postgres (origin from system R, originally meant for mutexes) 🕊️

Signals can be blocked or unblocked by various means (e.g., sigstop, sigcont, sigtstp) ⏰

Window signals: emulate signals on Windows (e.g., poll, select, k-event, e-poll) 🚀

Real-time signals: not covered in this talk, but important for timely responses ⏰

Signal handlers must be async signal-safe 💯

Signal handlers should not be called from signal handlers 🚫

Postgres emulates signals on Windows to stabilize code (e.g., spinlocks, latches) ⛔️

Power management: efficient use of resources, energy management ⏯️

Atomic operations: for updating flags in distributed systems 🔩

Poll: superseded by e-poll and k-event on modern systems ⚡️

BPatches: bug fixes that directly target issues in signal handling ⚠️