Re: What is the motivation of include directive and

From: "Bruce Momjian" <bruce(at)momjian(dot)us>
> Takayuki Tsunakawa wrote:
>> In section "17.1. Setting Parameters", include directive is
described.
>> Why was this directive prepared? What usage is assumed? Is it for
>> GUI tools, or for placing custom parameters in other files?
>>
>> In section "17.2. File Locations", the following parameters are
>> described:
>> What demand is assumed for placing configuration files outside the
>> data directory? Is it for placing configuration files in /etc to
>> conform to the FHS (Filesystem Hierarchy Standard, as documented
>> below) to enable the backup of all configuration files on the
system?
>
> It was designed for people who have multiple postmasters, but and
want
> to centralize some of that configuation.

Thank you. But I'm still a bit unclear.
Do you mean those functionalities were designed for, e.g.,
organizations that provide hosting service -- runs multiple database
instances on a single large machine? The image is:

/DataDirForCustomer1/postgresql.conf
[content]
include '/etc/postgresql_common.conf'
hba_file='/etc/pg_hba.conf'
...settings specific to customer 1

/DataDirForCustomer2/postgresql.conf
[content]
include '/etc/postgresql_common.conf'
hba_file='/etc/pg_hba.conf'
...settings specific to customer 2

/etc/postgresql_common.conf
[content]
...settings common among all customers

Was this mechanism invented in response to the demand from users, or
invented from the idea of PostgreSQL developers?

Still, I don't understand well why config files need to be placed
outside the data directory, except for daring conform to FHS.