RE: [EXTERNAL] Re: FDW, connections, master v replica

OK – so using target_session_attr=’read-write’ will use the show transaction_read_only command – if the reply is ‘on’ the connection is closed, which will then go to the next host/port combination… Seems to me, then, it’s the libpq operation that permits the selection…

Nice… Thanks very much.

From: Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
Sent: Tuesday, May 18, 2021 11:28 AM
To: Godfrin, Philippe E <Philippe(dot)Godfrin(at)nov(dot)com>; pgsql-admin(at)lists(dot)postgresql(dot)org
Subject: Re: [EXTERNAL] Re: FDW, connections, master v replica

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On Tue, 2021-05-18 at 16:13 +0000, Godfrin, Philippe E wrote:
> That seems very promising, though I’m not certain how I’d code that in the create
> foreign server syntax. My testbed is not quire ready right now, so I’ll ask instead of testing.
> Is this what you mean:
>
> CREATE SERVER FDW001 FOREIGN DATA WRAPPER POSTGES_FDW
> OPTIONS (HOST ‘FOORW, FOORO’, DBNAME ‘FOODB,FOODB’, PORT ‘5432,6432’,
> TARGET_SESSION_ATTRS ‘ANY,READ-ONLY’

Pretty much, yes. Except you can only specify a single setting for
"target_session_attrs".

Yours,
Laurenz Albe
--
Cybertec | https://www.cybertec-postgresql.com