Re: Potential ABI breakage in upcoming minor releases

Aleksander Alekseev <aleksander@timescale.com> writes:
> Hi Macro,
>> The problem here is that because TimescaleDB compiled against 17.0
>> assumes a struct size of 376 (on my laptop) while PostgreSQL allocated
>> the array with a struct size of 384, so the pointer math no longer
>> holds and the whichrel value becomes nonsense. (1736263376 for
>> whatever reason)

> Thanks for reporting. Yes, the code assumed fixed
> sizeof(ResultRelInfo) within a given PG major release branch which
> turned out not to be the case. We will investigate whether it can be
> easily fixed on TimescaleDB side.

Yeah, the array-stride problem seems extremely hard to work around,
because whichever size it is, you can't get code compiled with the
other size to work.  I believe ResultRelInfo is the only node type
we use arrays of, so this was a particularly unfortunate place
to break ABI, but there it is.

I'm starting to lean to the opinion that we need a re-wrap.
Given that padding holes exist, the code changes shouldn't
be big.

            regards, tom lane