Re: AIO v2.0

Hi,

On 2024-12-19 17:34:29 -0500, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > My current thoughts around this are that we should generally, independent of
> > io_uring, increase the FD limit ourselves.
>
> I'm seriously down on that, because it amounts to an assumption that
> we own the machine and can appropriate all its resources.  If ENFILE
> weren't a thing, it'd be all right, but that is a thing.  We have no
> business trying to consume resources the DBA didn't tell us we could.

Arguably the configuration *did* tell us, by having a higher hard limit...

I'm not saying that we should increase the limit without a bound or without a
configuration option, btw.

As I had mentioned, the problem with relying on increasing the soft limit that
is that it's not generally sensible to do so, because it causes a bunch of
binaries to do be weirdly slow.

Another reason to not increase the soft rlimit is that doing so can break
programs relying on select().

But opting into a higher rlimit, while obviously adhering to the hard limit
and perhaps some other config knob, seems fine?

Greetings,

Andres Freund