Re: pgsql: Prefetch data referenced by the WAL, take II.

On Sun, Sep 4, 2022 at 7:54 PM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> On 2022-Apr-07, Thomas Munro wrote:
> I propose a small wording change in guc.c,
>
> diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
> index 9fbbfb1be5..9803741708 100644
> --- a/src/backend/utils/misc/guc.c
> +++ b/src/backend/utils/misc/guc.c
> @@ -2840,7 +2840,7 @@ static struct config_int ConfigureNamesInt[] =
>         {
>                 {"wal_decode_buffer_size", PGC_POSTMASTER, WAL_RECOVERY,
>                         gettext_noop("Maximum buffer size for reading ahead in the WAL during recovery."),
> -                       gettext_noop("This controls the maximum distance we can read ahead in the WAL to prefetch
referencedblocks."),
 
> +                       gettext_noop("This controls the maximum distance we can read ahead in the WAL to prefetch
datablocks referenced therein."),
 
>                         GUC_UNIT_BYTE
>                 },
>                 &wal_decode_buffer_size,
>
> "referenced blocks" seems otherwise a bit unclear to me.  Other wording
> suggestions welcome.  I first thought of "...to prefetch referenced data
> blocks", which is probably OK too.

I'd go for your second suggestion.  'therein' doesn't convey much (we
already said 'in the WAL', and therein is just a slightly formal and
somehow more Germanic way of saying 'in it' which is kinda
duplicative; maybe 'by it' is what we want but that's still kinda
implied already), whereas adding 'data' makes it slightly clearer that
it's blocks from relations and not, say, the WAL itself.

Also, hmm, it's not really the 'Maximum buffer size', it's the 'Buffer size'.