Re: export FUNC_MAX_ARGS as a read-only GUC variable

Tom Lane wrote:
> One could make a good case that INDEX_MAX_KEYS should be exported along
> with FUNC_MAX_ARGS, rather than letting people write client code that
> assumes they are the same.
>
> I was intending to propose that we also export the following as
> read-only variables:
> * NAMEDATALEN
> * BLCKSZ
> * integer-vs-float datetime flag

OK, the attached includes the above -- result looks like:

regression=# select * from pg_settings where category like 'Compile%';
-[ RECORD 1 ]----------------------------------------------
name | block_size
setting | 8192
category | Compiled-in Options
short_desc | Shows size of a disk block
extra_desc |
context | internal
vartype | integer
source | default
min_val | 8192
max_val | 8192
-[ RECORD 2 ]----------------------------------------------
name | func_max_args
setting | 32
category | Compiled-in Options
short_desc | Shows the maximum number of function arguments
extra_desc |
context | internal
vartype | integer
source | default
min_val | 32
max_val | 32
-[ RECORD 3 ]----------------------------------------------
name | index_max_keys
setting | 32
category | Compiled-in Options
short_desc | Shows the maximum number of index keys
extra_desc |
context | internal
vartype | integer
source | default
min_val | 32
max_val | 32
-[ RECORD 4 ]----------------------------------------------
name | integer_datetimes
setting | on
category | Compiled-in Options
short_desc | Datetimes are integer based
extra_desc |
context | internal
vartype | bool
source | default
min_val |
max_val |
-[ RECORD 5 ]----------------------------------------------
name | name_data_len
setting | 63
category | Compiled-in Options
short_desc | Shows the maximum identifier length
extra_desc |
context | internal
vartype | integer
source | default
min_val | 63
max_val | 63

> If it's there it should be separate. I think also there was some
> feeling it should be called "extra_desc" not "long_desc".

Done. Also added "category" which displays config_group_names[conf->group]

> Please set the GUC_NOT_IN_SAMPLE and GUC_DISALLOW_IN_FILE flag bits on
> each of these variables, too. I know we are not using these flags for
> anything yet, but we should try to get them right...

Done.

I'll update the docs once I'm sure we're done iterating on these changes.

Any further comments?

Joe