Re: Make pg_stat_io view count IOs as bytes instead of blocks

Hi,

On Tue, 24 Dec 2024 at 09:13, Michael Paquier <michael@paquier.xyz> wrote:
>
> On Fri, Dec 06, 2024 at 12:41:55PM +0300, Nazir Bilal Yavuz wrote:
> > Thanks! I think 'track' is a better word in this context. I used
> > 'tracked in ...', as it sounded more correct to me (I hope it is).
>
> Splitting op_bytes into three fields sounds like a good idea.  Count
> me in regarding the concept to depend less on BLCKSZ.
>
>  typedef enum IOOp
>  {
> +       /* IOs not tracked in bytes */
>         IOOP_EVICT,
> -       IOOP_EXTEND,
>         IOOP_FSYNC,
>         IOOP_HIT,
> -       IOOP_READ,
>         IOOP_REUSE,
> -       IOOP_WRITE,
>         IOOP_WRITEBACK,
> +
> +       /* IOs tracked in bytes */
> +       IOOP_EXTEND,
> +       IOOP_READ,
> +       IOOP_WRITE,
>  } IOOp;
>
> pg_stat_io_build_tuples() is now the code path taken when building the
> tuples returned by pg_stat_io, meaning that the new function called
> pg_stat_get_backend_io() is also going to need an update in its list
> of output parameters to accomodate with what you are changing here.
> Calling your new pgstat_get_io_byte_index() in the new refactored
> routine is also necessary.  Sorry about that.

No problem at all, thank you for reminding me!

> Could you send a rebase, please?  I can promise to review this
> thread's new patch, as that will also move the needle regarding your
> work with pg_stat_io to track WAL activity.

Thanks! v4 is attached. I quickly tested the pg_stat_get_backend_io()
function and it seems it is working.

-- 
Regards,
Nazir Bilal Yavuz
Microsoft