IPC in PostgreSQL
summary
Postgres moves from polling and blocking IO toward precise nonblocking wakeups using a check_for_interrupt cooperative hook, shared-memory latches (added 2010) and epoll/kqueue multiplexing; the postmaster refactor in v16 removes risky fork-inside-handler code and the walreceiver stops waking 10×/sec. IPC uses PM signals and proc signals (including a recent proc signal barrier that asks every backend to reach its next interrupt point). Remaining work includes finer-grained interrupt masks and a nonblocking subprocess module to avoid blocking while running archiver/copy programs.
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chapters (14)
- 0:00Introduction
- 4:10Hardware
- 11:14Common mistakes
- 21:14Sleeping system calls
- 22:59Latches
- 24:14Latch
- 31:44PM Signals
- 33:44Proc Signals
- 35:10Proximal Barrier
- 36:27Check for interrupts
- 39:25Improvements
- 40:15Subprocess module
- 41:01Possible changes
- 41:18The Unix way
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