Обсуждение: [GENERAL] Add NAMEDATALEN to PG_CONFIG?

Is there a way to find NAMEDATALEN in a database, other than looking at the source? If not could it be added to the PG_CONFIG eventually?

Andy Johnson

On 05/15/2017 04:27 PM, Andy Johnson wrote:
> Is there a way to find NAMEDATALEN in a database, other than looking at
> the source? If not could it be added to the PG_CONFIG eventually?
>
> Andy Johnson
>

https://www.postgresql.org/docs/9.6/static/runtime-config-preset.html

"max_identifier_length (integer)

     Reports the maximum identifier length. It is determined as one less
than the value of NAMEDATALEN when building the server. The default
value of NAMEDATALEN is 64; therefore the default max_identifier_length
is 63 bytes, which can be less than 63 characters when using multibyte
encodings.
"

So:

production=# show max_identifier_length ;
  max_identifier_length
-----------------------
  63


--
Adrian Klaver
adrian.klaver@aklaver.com

Andy Johnson <andy@asjohnson.com> writes:
> Is there a way to find NAMEDATALEN in a
> database, other than looking at the
> source?

select typlen from pg_type where typname = 'name';

> If not could it be added to the
> PG_CONFIG eventually?

Seems like it would only make sense to do that if we supported
configuring NAMEDATALEN, which we don't really: you have to
manually edit pg_config_manual.h, and how well the result works
is on your own head.

            regards, tom lane