Re: Revisiting NAMEDATALEN

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Emrul <emrul(at)emrul(dot)com>
Cc: "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Revisiting NAMEDATALEN
Date: 2017-07-07 11:29:06
Message-ID: CA+TgmoZ7vtzX=Ry2TYLrAborWUxwUWbHCAO13wpPdsKr=iy6rQ@mail.gmail.com
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On Fri, Jul 7, 2017 at 5:53 AM, Emrul <emrul(at)emrul(dot)com> wrote:
> Tom, thank you for that pointer. I get now that it is not free and therefore
> why its not something that should be changed by default.
>
> I guess the problem is 'build your own copy' (i.e. compiling from source) is
> something that sends most DB teams running into the hills.
>
> A solution might be to make NAMEDATALEN configurable without having to
> recompile source (perhaps a config variable or an initdb parameter). When I
> have some free time I will investigate whether this is doable.

Well, it wouldn't be free. The problem is:

typedef struct nameData
{
char data[NAMEDATALEN];
} NameData;

If it were not a compile-time constant, every bit of code that uses
NameData (or otherwise depends on NAMEDATALEN being constant) would
have to be changed. That would be invasive and likely have at least a
minor performance cost.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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