Schedule - PostgreSQL Development Conference 2024
Streaming I/O and vectored I/O
Date: 2024-05-29
Time: 09:00–09:50
Room: Fletcher(1900)
Level: Advanced
Streaming I/O and vectored I/O
Traditionally, PostgreSQL did all relation I/O as sequential 8KB pread() or pwrite() system calls. This talk is about a new "streaming" programming model that allows multiple blocks to be read or written at the same time, and eventually in the background ahead of time.
I will talk about several things that cover recent and ongoing commits:
- overview of system file I/O interfaces
- storage manager changes for multi-buffer operations
- buffer manager changes for multi-buffer operations
- the stream abstraction
- "synchronous" streaming I/O
- partial steps to asynchronous I/O
- use cases (heap/index scans, vacuum, recovery, ...)
This corresponds to commitfest entry https://commitfest.postgresql.org/46/4532/ (and earlier related work).
I will also talk more briefly about some aspects of the next stages of the larger AIO project:
- overview of kernel buffering, pros, cons and motivations for escaping from it
- why asynchronous I/O and direct I/O go together
- a peek at WIP asynchronous I/O system
- asynchronous streaming I/O
