Re: Remove unused 'len' from pg_stat_recv_* functions

At Tue, 3 Aug 2021 12:40:23 +0900, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote in
> Hi all,
>
> While working on a patch adding new stats, houzj pointed out that
> 'len' function arguments of all pgstat_recv_* functions are not used
> at all. Looking at git history, pgstat_recv_* functions have been
> having ‘len’ since the stats collector was introduced by commit
> 140ddb78fe 20 years ago but it was not used at all even in the first
> commit. It seems like the improvements so far for the stats collector
> had pgstat_recv_* function have ‘len’ for consistency with the
> existing pgstat_recv_* functions. Is there any historical reason for
> having 'len' argument? Or can we remove them?
>
> I've attached the patch that removes 'len' from all pgstat_recv_* functions.

I at the first look thought that giving "len" as a parameter is
reasonable as message-processing functions, but the given message
struct contains the same value and the functions can refer to the
message length without the parameter if they want. So I'm +-0 for the
removal.

It applies cleanly on the master and compiled without an error.

That being said, I'm not sure it is worthwhile to change parameters of
going-to-be-removed functions (if shared-memory stats collector is
successfully introduced).

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center