Hi, On 2024-09-05 01:37:34 +0800, 陈宗志 wrote: > I hope there can be a high-level design document that includes a > description, high-level architecture, and low-level design. > This way, others can also participate in reviewing the code.
Yep, that was already on my todo list. The version I just posted includes that. > For example, which paths were modified in the AIO module? > Is it the path for writing WAL logs, or the path for flushing pages, etc.? I don't think it's good to document this in a design document - that's just bound to get out of date. For now the patchset causes AIO to be used for 1) all users of read_stream.h, e.g. sequential scans 2) bgwriter / checkpointer, mainly to have way to exercise the write path. As mentioned in my email upthread, the code for that is in a somewhat rough shape as Thomas Munro is working on a more general abstraction for some of this. The earlier patchset added a lot more AIO uses because I needed to know all the design constraints. It e.g. added AIO use in WAL. While that allowed me to learn a lot, it's not something that makes sense to continue working on for now, as it requires a lot of work that's independent of AIO. Thus I am focusing on the above users for now. > Also, I recommend keeping this patch as small as possible. Yep. That's my goal (as mentioned upthread). > For example, the first step could be to introduce libaio only, without > considering io_uring, as that would make it too complex. Currently the patchset doesn't contain libaio support and I am not planning to work on using libaio. Nor do I think it makes sense for anybody else to do so - libaio doesn't work for buffered IO, making it imo not particularly useful for us. The io_uring specific code isn't particularly complex / large compared to the main AIO infrastructure. Greetings, Andres Freund
