PostgreSQL and Linux Kernel interactions
summary
Shows how PostgreSQL actually calls the kernel: process forks use clone to spawn workers, shared memory uses mmap MAP_SHARED, and signals implement latch coordination (WaitLatch/SetLatch) rather than vague “IPC.” Demonstrations use strace, perf, fincore and /proc to find where postgres blocks, quantify double buffering (kernel page cache plus Postgres buffers), and show that enabling direct I/O removes kernel caching. Examples cover copy_file_range and io_uring usage, PG16/17 vectorized preads, fallocate, sync_file_range, and prefetch via fadvise.
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chapters (10)
- 0:00Introduction
- 2:45What are you going to learn?
- 5:32Strace basics
- 7:20Interactions with kernel (high level view)
- 9:27System call examples
- 13:28Process management
- 15:22Memory, Signals
- 20:03Buffered & Direct I/O
- 24:42With and without I/O Combining (PG16 & PG17)
- 25:33Prefetch, Misc system calls, New usages
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