Horton

Re: RFC: Allow EXPLAIN to Output Page Fault Information

Jelte Fennema-Nio <postgres@jeltef.nl>

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From: Jelte Fennema-Nio <postgres@jeltef.nl>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, torikoshia <torikoshia@oss.nttdata.com>, pgsql-hackers@postgresql.org, rjuju123@gmail.com, Bruce Momjian <bruce@momjian.us>
Date: 2025-02-11T17:45:13Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Avoid leaking system path from pg_available_extensions

  2. Enable BUFFERS with EXPLAIN ANALYZE by default

On Tue, 11 Feb 2025 at 17:19, Andres Freund <andres@anarazel.de> wrote:
> Yes, at least initially:

Ah, then I understand your point of view much better. Still I think we
could easily frame it as: If you enable io_uring, you also get these
additional fancy stats.

Also afaict the items don't have to mean that

> 1) it's not enabled on the kernel level everywhere

Is that really a common thing to do? From a quick internet search, I
can "only" find that Google does this. (Google is definitely a big
cloud player, so I don't want to suggest that that is not important,
but if that's really the only one still the bulk of systems would have
io_uring support)

> 2) it requires an optional build dependency

What build dependency is this? In any case, can't we choose the
default at build time based on the available build dependencies? And
if we cannot, I think we could always add an "auto" default that would
mean the best available AIO implementation (where io_uring is better
than bgworkers).

> 3) it requires tuning the file descriptor ulimit, unless we can convince Tom
>    that it's ok to do that ourselves

I think we should just do this, given the reasoning in the blog[1]
from the systemd author I linked in the AIO thread. I agree that a
response/explicit approval from Tom would be nice though.

[1]: https://0pointer.net/blog/file-descriptor-limits.html