Re: JIT performance bug/regression & JIT EXPLAIN

On Fri, Nov 15, 2019 at 5:49 AM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> Personally, I don't care very much about backward-compatibility, or
> about how hard it is for tools to parse. I want it to be possible, but
> if it takes a little extra effort, so be it.

I think these are two separate issues. I agree on
backward-compatibility (especially if we can embed a server version in
structured EXPLAIN output to make it easier for tools to track format
differences), but not caring how hard it is for tools to parse? What's
the point of structured formats, then?

> My main concern is having
> the text output look good to human beings, because that is the primary
> format and they are the primary consumers.

Structured output is also for human beings, albeit indirectly. That
text is the primary format may be more of a reflection of the
difficulty of building and integrating EXPLAIN tools than its inherent
superiority (that said, I'll concede it's a concise and elegant format
for what it does). What if psql supported an EXPLAINER like it does
EDITOR?

For what it's worth, after thinking about this a bit, I'd like to see
structured EXPLAIN evolve into a more consistent format, even if it
means breaking changes (and I do think a version specifier at the root
of the plan would make this easier).