Greetings,
* David Fetter (david@fetter.org) wrote:
> On Tue, Jan 14, 2020 at 12:53:04PM -0500, Tom Lane wrote:
> > Robert Haas <robertmhaas@gmail.com> writes:
> > > ... I would also expect that depending on an external package
> > > would provoke significant opposition. If we suck the code into core,
> > > then we have to keep it up to date with the upstream, which is a
> > > significant maintenance burden - look at all the time Tom has spent on
> > > snowball, regex, and time zone code over the years.
> >
> > Also worth noting is that we have a seriously bad track record about
> > choosing external packages to depend on. The regex code has no upstream
> > maintainer anymore (well, the Tcl guys seem to think that *we* are
> > upstream for that now), and snowball is next door to moribund.
> > With C not being a particularly hip language to develop in anymore,
> > it wouldn't surprise me in the least for any C-code JSON parser
> > we might pick to go dead pretty soon.
>
> Given jq's extreme popularity and compatible license, I'd nominate that.
I don't think that really changes Tom's concerns here about having an
"upstream" for this.
For my part, I don't really agree with the whole "we don't want two
different JSON parsers" when we've got two of a bunch of stuff between
the frontend and the backend, particularly since I don't really think
it'll end up being *that* much code.
My thought, which I had expressed to David (though he obviously didn't
entirely agree with me since he suggested the other options), was to
adapt the pgBackRest JSON parser, which isn't really all that much code.
Frustratingly, that code has got some internal pgBackRest dependency on
things like the memory context system (which looks, unsurprisingly, an
awful lot like what is in PG backend), the error handling and logging
systems (which are different from PG because they're quite intentionally
segregated from each other- something PG would benefit from, imv..), and
Variadics (known in the PG backend as Datums, and quite similar to
them..).
Even so, David's offered to adjust the code to use the frontend's memory
management (*cough* malloc()..), and error handling/logging, and he had
some idea for Variadics (or maybe just pulling the backend's Datum
system in..? He could answer better), and basically write a frontend
JSON parser for PG without too much code, no external dependencies, and
to make sure it answers this requirement, and I've agreed that he can
spend some time on that instead of pgBackRest to get us through this, if
everyone else is agreeable to the idea. Obviously this isn't intended
to box anyone in- if there turns out even after the code's been written
to be some fatal issue with using it, so be it, but we're offering to
help.
Thanks,
Stephen
