Re: display hot standby state in psql prompt

On Wed, Jun 25, 2025 at 11:50 AM Jim Jones <jim(dot)jones(at)uni-muenster(dot)de>
wrote:

> Since I cannot get the value of transaction_read_only via
> PQparameterStatus.

Hmmm... we can at least get default_transaction_read_only. As fe-connect.c
points out:
/*
* "transaction_read_only = on" proves that at least one
* of default_transaction_read_only and in_hot_standby
is
* on, but we don't actually know which. We don't care
* though for the purpose of identifying a read-only
* session, so satisfy the CONNECTION_CHECK_TARGET code
by
* claiming they are both on. On the other hand, if
it's
* a read-write session, they are certainly both off.
*/
Maybe that's good enough? It won't detect people starting a new transaction
and declaring it read-only, but it should be sufficient to warn people when
a connection is starting out in a read-only state. And it will still toggle
auto-magically on promotion.

Cheers,
Greg

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