Re: Reducing output size of nodeToString

On Thu, 7 Dec 2023 at 13:09, David Rowley <dgrowleyml@gmail.com> wrote:
>
> On Thu, 7 Dec 2023 at 10:09, Matthias van de Meent
> <boekewurm+postgres@gmail.com> wrote:
> > PFA a patch that reduces the output size of nodeToString by 50%+ in
> > most cases (measured on pg_rewrite), which on my system reduces the
> > total size of pg_rewrite by 33% to 472KiB. This does keep the textual
> > pg_node_tree format alive, but reduces its size significantly.
>
> It would be very cool to have the technology proposed by Andres back
> in 2019 [1]. With that, we could easily write various output
> functions.  One could be compact and easily machine-readable and
> another designed to be better for humans for debugging purposes.
>
> We could also easily serialize plans to binary format for copying to
> parallel workers rather than converting them to a text-based
> serialized format. It would also allow us to do things like serialize
> PREPAREd plans into a nicely compact single allocation that we could
> just pfree in a single pfree call on DEALLOCATE.

I'm not sure what benefit you're refering to. If you mean "it's more
compact than the current format" then sure; but the other points can
already be covered by either the current nodeToString format, or by
nodeCopy-ing the prepared plan into its own MemoryContext, which would
allow us to do essentially the same thing.

> Likely we could just use the existing Perl scripts to form the
> metadata arrays rather than the clang parsing stuff Andres used in his
> patch.
>
> Anyway, just wanted to ensure you knew about this idea.

I knew about that thread thread, but didn't notice the metadata arrays
part of it, which indeed looks interesting for this patch. Thanks for
pointing it out. I'll see if I can incorporate parts of that into this
patchset.

Kind regards,

Matthias van de Meent
Neon (https://neon.tech)