Re: Add Pipelining support in psql

Anthonin Bonnefoy wrote:

> > What is the reasoning here behind this restriction? \gx is a wrapper
> > of \g with expanded mode on, but it is also possible to call \g with
> > expanded=on, bypassing this restriction.
>
> The issue is that \gx enables expanded mode for the duration of the
> query and immediately reset it in sendquery_cleanup. With pipelining,
> the command is piped and displaying is done by either \endpipeline or
> \getresults, so the flag change has no impact. Forbidding it was a way
> to make it clearer that it won't have the expected effect

But it's not just \gx

The following invocations don't respect the desired output destination
and formats (ignoring them), when a pipeline is active:

select ... \bind \g filename
select ... \bind \g |program
select ... \bind \g (format=unaligned tuples_only=on)

Just like for \gx the problem is that in a pipeline, sending the query
is not followed by getting the results, and the output properties
of a query are lost in between.

Best regards,
--
Daniel Vérité
https://postgresql.verite.pro/