Re: AIO v2.2

On Wed, Jan 8, 2025 at 7:26 PM Andres Freund <andres(at)anarazel(dot)de> wrote:
> 1) Shared memory representation of an IO, for the AIO subsystem internally
>
> Currently: PgAioHandle
>
> 2) A way for the issuer of an IO to reference 1), to attach information to the
> IO
>
> Currently: PgAioHandle*
>
> 3) A way for any backend to wait for a specific IO to complete
>
> Currently: PgAioHandleRef

With that additional information, I don't mind this naming too much,
but I still think PgAioHandle -> PgAio and PgAioHandleRef ->
PgAioHandle is worth considering. Compare BackgroundWorkerSlot and
BackgroundWorkerHandle, which suggests PgAioHandle -> PgAioSlot and
PgAioHandleRef -> PgAioHandle.

> ZOMBIE feels even later than REAPED to me :)

Makes logical sense, because you would assume that you die first and
then later become an undead creature, but the UNIX precedent is that
dying turns you into a zombie and someone then has to reap the exit
status for you to be just plain dead. :-)

> > I do agree with Heikki that REAPED sounds later than COMPLETED, because you
> > reap zombie processes by collecting their exit status. Maybe you could have
> > AHS_COMPLETE or AHS_IO_COMPLETE for the state where the I/O is done but
> > there's still completion-related work to be done, and then the other state
> > could be AHS_DONE or AHS_FINISHED or AHS_FINAL or AHS_REAPED or something.
>
> How about
>
> AHS_COMPLETE_KERNEL or AHS_COMPLETE_RAW - raw syscall completed
> AHS_COMPLETE_SHARED_CB - shared callback completed
> AHS_COMPLETE_LOCAL_CB - local callback completed
>
> ?

That's not bad. I like RAW better than KERNEL. I was hoping to use
different works like COMPLETE and DONE rather than, as you did it
here, COMPLETE and COMPLETE, but it's probably fine.

--
Robert Haas
EDB: http://www.enterprisedb.com