Re: Direct I/O - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Direct I/O
Date
Msg-id 1557292.1681501109@sss.pgh.pa.us
Whole thread Raw
In response to Re: Direct I/O  (Andres Freund <andres@anarazel.de>)
Responses Re: Direct I/O
List pgsql-hackers
Andres Freund <andres@anarazel.de> writes:
> On 2023-04-14 15:21:18 -0400, Tom Lane wrote:
>> +1 for that, though.  (Also, the fact that these animals aren't
>> actually failing suggests that 004_io_direct.pl needs expansion.)

> It's skipped, due to lack of O_DIRECT:
> [20:50:22] t/004_io_direct.pl .............. skipped: no O_DIRECT

Hmm, I'd say that might be just luck.  Whether the compiler honors weird
alignment of locals seems independent of whether the OS has O_DIRECT.

> So perhaps we don't even need a configure test, just a bit of ifdef'ery? It's
> a bit annoying structurally, because the PG*Aligned structs are defined in
> c.h, but the different ways of spelling O_DIRECT are dealt with in fd.h.

> I wonder if we should try to move those structs to fd.h as well...

I doubt they belong in c.h, so that could be plausible; except
I'm not convinced that testing O_DIRECT is sufficient.

            regards, tom lane



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