Обсуждение: BUG #16628: Hostame and string connection functions

The following bug has been logged on the website:

Bug reference:      16628
Logged by:          Anderson Antunes
Email address:      anderson.ant.oli@gmail.com
PostgreSQL version: 9.5.0
Operating system:   Linux
Description:

Hi,

Is there any possibility of developing a function to retrieve hostname and
the connection string?

Example:

select get_host_name ();
select get_string_connection ();

On Tue, Sep 22, 2020 at 06:57:13PM +0000, PG Bug reporting form wrote:
> The following bug has been logged on the website:
> 
> Bug reference:      16628
> Logged by:          Anderson Antunes
> Email address:      anderson.ant.oli@gmail.com
> PostgreSQL version: 9.5.0
> Operating system:   Linux
> Description:        
> 
> Hi,
> 
> Is there any possibility of developing a function to retrieve hostname and
> the connection string?
> 
> Example:
> 
> select get_host_name ();

You can get the server IP address, but not the host name:

    test=> SELECT inet_server_addr();
     inet_server_addr
    ------------------
     127.0.0.1

> select get_string_connection ();

Uh, the connection information is parsed by libpq, and visible in psql:

    test=> \conninfo You are connected to database "test" as user
        "postgres" on host "localhost" (address "127.0.0.1")
        at port "5432".

but the server only sees the result.  You can see the server port
number:

    test=> SELECT inet_server_port();
     inet_server_port
    ------------------
                 5432

I can't figure out how to query the SSL mode via SQL.  Does this help?

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

  The usefulness of a cup is in its emptiness, Bruce Lee

On Sat, Apr 22, 2023 at 11:57:06AM -0300, Anderson Antunes wrote:
> I'm sorry for not responding earlier. She ended up falling into spam. I solved
> it by creating a specific variable in the postgresql configuration file.
> 
> If it's not too much trouble, I have another question: my name is Anderson
> Antunes. I live in Brazil. I'm doing research for a master's project about
> pseudo random numbers and would like to know more information about the random
> () function used to randomly order a set of records. I tried to search through
> the site that offers the source code but I couldn't identify the exact
> implementation of this function. 

Looks like random() internally is called drandom():

    \x
    \df+ random
    List of functions
    -[ RECORD 1 ]-------+-----------------
    Schema              | pg_catalog
    Name                | random
    Result data type    | double precision
    Argument data types |
    Type                | func
    Volatility          | volatile
    Parallel            | restricted
    Owner               | postgres
    Security            | invoker
    Access privileges   |
    Language            | internal
-->    Internal name       | drandom
    Description         | random value

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Embrace your flaws.  They make you human, rather than perfect,
  which you will never be.