From: pgsql-hackers-owner@postgresql.org
> [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Craig Ringer
> On 13 April 2017 at 14:59, Tsunakawa, Takayuki
> <tsunakawa.takay@jp.fujitsu.com> wrote:
>
> > 2. Make transaction_read_only GUC_REPORT This is to avoid the added
> > round-trip by SHOW command. It also benefits client apps that want to
> know when the server gets promoted? And this may simplify the libpq code.
> > I don't understand yet why we need to provide this feature for older servers
> by using SHOW. Those who are already using <= 9.6 in production completed
> the system or application, and their business is running. Why would they
> want to just replace libpq and use this feature?
>
> I think "transaction_read_only" is a bit confusing for something we're
> expecting to change under us.
>
> To me, a "read only" xact is one created with
>
> BEGIN READ ONLY TRANSACTION;
>
> .... which I would not expect to become read/write under me, since I
> explicitly asked for read-only.
>
> It's more like "session read only" that we're interested in IMO.
Are you suggest thating we provide a GUC_REPORT read-only variable "session_read_only" and the libpq should use it?
Anyway, I added this item in the PostgreSQL 10 Open Items page under
"Design Decisions to Recheck Mid-Beta". I'm willing to submit a patch for PG10.
Regards
Takayuki Tsunakawa
