Re: [PATCH] Add get_bytes() and set_bytes() functions

Hi,

> When we add such casts between bytea and the integer/numeric types,
> one of the problems mentioned the first of the thread, that is,
> "we don't have a convenient way of casting a bytea to an integer / bigint
> and vice versa", would seem be resolved.
>
> On the other hand, I suppose get_bytes() and set_bytes() are still useful
> for extracting bytes from byteas, etc. If casting is no longer the main
> purpose of these functions, are variations that get_bytes returns bytea
> instead of bigint, and set_bytes receives bytea as the newvalue argument
> useful? I wonder it would eliminate the restrict that size cannot be larger
> than 8.

No, casting between bytea and numeric will not replace get_bytes() /
set_bytes() for performance reasons.

Consider the case when you want to extract an int4 from a bytea.
get_bytes() is going to be very fast while substr() -> ::numeric ->
::integer chain will require unnecessary copying and conversions.
Casting between bytea and numeric is only useful when one has to deal
with integers larger than 8 bytes. Whether this happens often is a
debatable question.

> Here are my very trivial comments on the patch.
>
> + * this routine treats "bytea" as an array of bytes.
>
> Maybe, the sentence should start with "This ... ".
>
> + while(size)
> + {
>
> I wonder inserting a space after "while" is the standard style.

Thanks, fixed.

--
Best regards,
Aleksander Alekseev