Re: should we document an example to set multiple libraries in shared_preload_libraries?

On Fri, Dec 3, 2021 at 11:25 PM Bossart, Nathan <bossartn@amazon.com> wrote:
>
> On 12/3/21, 6:21 AM, "Bharath Rupireddy" <bharath.rupireddyforpostgres@gmail.com> wrote:
> > +1 to add here in the "Parameter Names and Values section", but do we
> > want to backlink every string parameter to this section? I think it
> > needs more effort. IMO, we can just backlink for
> > shared_preload_libraries alone. Thoughts?
>
> IMO this is most important for GUC_LIST_QUOTE parameters, of which
> there are only a handful.  I don't think adding a link to every string
> parameter is necessary.

Agree.

Should we specify something like below in the "Parameter Names and
Values" section's "String:" para? Do we use generic terminology like
'name' and val1, val2, val3 and so on?

ALTER SYSTEM SET name = val1,val2,val3;
ALTER SYSTEM SET name = 'val1', 'val2', 'val3';
ALTER SYSTEM SET name = '"val 1"', '"val,2"', 'val3';

Another thing I observed is the difference between how the
postgresql.conf file and ALTER SYSTEM SET command is parsed for
GUC_LIST_QUOTE values.

For instance, in postgresql.conf file, by default search_path is
specified as follows:
search_path = '"$user", public',
postgres=# show search_path ;
   search_path
-----------------
 "$user", public
(1 row)

When I use the same style with ALTER SYSTEM SET command, the value is
treated as single string value:
postgres=# ALTER SYSTEM SET search_path = '"$user", public';
ALTER SYSTEM
postgres=# show search_path ;
   search_path
-----------------
 "$user", public
(1 row)

postgres=# select pg_reload_conf();
 pg_reload_conf
----------------
 t
(1 row)

postgres=# show search_path ;
     search_path
---------------------
 """$user"", public"
(1 row)

Am I missing something here? Or is there a distinction between parsing
of postgresql.conf and ALTER SYSTEM SET command for GUC_LIST_QUOTE
values? If so, what is it?

Regards,
Bharath Rupireddy.