Re: Add Pipelining support in psql

On Wed, 27 Nov 2024 at 14:50, Anthonin Bonnefoy
<anthonin(dot)bonnefoy(at)datadoghq(dot)com> wrote:
>
> Hi,
>
> With \bind, \parse, \bind_named and \close, it is possible to issue
> queries from psql using the extended protocol. However, it wasn't
> possible to send those queries using pipelining and the only way to
> test pipelined queries was through pgbench's tap tests.

Hello, good concept. Our connection pooler testing will greatly
benefit from this feature. At the moment, our tests are golang-based
and build pipelines in extended proto and verify the outcome.
Regression tests based on SQL will be far more thorough and organic.

> The attached patch adds pipelining support to psql with 3 new
> meta-commands, mirroring what's already done in pgbench:
> - \startpipeline starts a new pipeline. All extended queries will be
> queued until the end of the pipeline is reached.
> - \endpipeline ends an ongoing pipeline. All queued commands will be
> sent to the server and all responses will be processed by the psql.
> - \syncpipeline queue a synchronisation point without flushing the
> commands to the server

I'm very doubtful about the \syncpipeline . Maybe we should instead
support \sync meta-command in psql? This will be a useful contribution
itself.

> Those meta-commands will allow testing pipelined query behaviour using
> psql regression tests.
>
> Regards,
> Anthonin

I haven't looked into the patch in detail yet.

--
Best regards,
Kirill Reshke