Re: DBLINK Error

On 02/09/2023 09:50 CEST Daulat <daulat(dot)dba(at)gmail(dot)com> wrote:

> I am facing an issue while fetching data using dblink.
> I am using a .pgpass file and MD5 for authentication.

What does ~postgres/.pgpass and pg_hba.conf look like?

> .pgpass file is located in the home directory (postgres user home) of the
> user running the PostgreSQL query. This file has proper permission 0600 and
> owner postgres to keep it secure. The OS is Amazon Linux.
>
> Connection made successfully without giving password.
>
> [root(at)DEM-MT bin]# ./psql -d postgres -U postgres
> psql (14.6)
> Type "help" for help.
>
> postgres=#

Does root also have a .pgpass file? Otherwise this looks like user postgres is
configured with trust authentication (at least on database postgres) if there's
no password prompt for user postgres.

> cd /opt/PostgreSQL-14/bin/
> [root(at)DEM-MT bin]# ./psql -d postgres -U postgres -W
> Password:
> psql (14.6)
> Type "help" for help.
>
> postgres=#

Does it accept any password? That would be the case for trust authentication.

> ERROR:
> -----------
>
> cd /opt/PostgreSQL-14/bin/
> [postgres(at)DMM-MT bin]$ ./psql -U postgres -d tn2_demo_10
>
> tn2_demo_10=# select * from ucf.dblink_connect_u('conn','dbname="ADT_DEM_DB"');
> ERROR: could not establish connection
> DETAIL: connection to server on socket "/tmp/.s.PGSQL.5432" failed: fe_sendauth: no password supplied

Okay, no trust authentication for user postgres on database ADT_DEM_DB. My
guess is an error in ~postgres/.pgpass so that libpq does not find a matching
entry for the connection.

--
Erik