Re: libpq pipelineing

Tom, I'm implementing a small abstraction layer for event-driven
result streaming on PostgreSQL and MariaDB for Ruby, and I'll endeavor
to report back with some numbers once I have enough of it working to
benchmark something meaningful.

Thanks for your patience and help.

Kind regards,
Samuel

On Tue, 30 Jun 2020 at 02:06, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> Samuel Williams <space(dot)ship(dot)traveller(at)gmail(dot)com> writes:
> > Those methods don't seem to have an equivalent in libpq - you can use
> > PQgetResult but it buffers all the rows. Using single row mode results
> > in many results for each query (seems like a big overhead).
>
> Have you got any actual evidence for that? Sure, the overhead is
> more than zero, but does it mean anything in comparison to the other
> costs of data transmission?
>
> > Maybe the statement about efficiency is incorrect, but it would be
> > nice if you could incrementally stream a single result set more
> > easily.
>
> More easily than what? If we did not construct a PGresult then we would
> need some other abstraction for access to the returned row, dealing with
> error cases, etc etc. That would mean a lot of very duplicative API code
> in libpq, and a painful bunch of adjustments in client code.
>
> regards, tom lane