Re: Hypothetical indexes using BRIN broken since pg10

On 2019-Sep-24, Julien Rouhaud wrote:

> On Mon, Sep 9, 2019 at 5:03 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> > Whether we should bother back-patching a less capable stopgap fix
> > is unclear to me. Yeah, it's a bug that an index adviser can't
> > try a hypothetical BRIN index; but given that nobody noticed till
> > now, it doesn't seem like there's much field demand for it.
> > And I'm not sure that extension authors would want to deal with
> > testing minor-release versions to see if the fix is in, so
> > even if there were a back-patch, it might go unused.
>
> FWIW I maintain such an extension and testing for minor release
> version is definitely not a problem.

I think the danger is what happens if a version of your plugin that was
compiled with the older definition runs in a Postgres which has been
recompiled with the new code. This has happened to me with previous
unnoticed ABI breaks, and it has resulted in crashes in production
systems. It's not a nice situation to be in.

If the break is benign, i.e. "nothing happens", then it's possibly a
worthwhile change to consider. I suppose the only way to know is to
write patches for both sides and try it out.

--
Álvaro Herrera https://www.2ndQuadrant.com/
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