Re: Should pg_dump refuse to run if DB has different version?

* Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> [000403 12:18] wrote:
> If you run 6.5 pg_dump against a 7.0 database, or vice versa,
> you get very obscure error messages:
> parseNumericArray: too many numbers
> getInherits(): SELECT failed. Explanation from backend: 'ERROR: Attribute 'inhrel' not found
> (Quick, guess which is which ... you'll probably guess wrong.)
>
> It's too late to do anything about the behavior of 6.5 pg_dump,
> but we could change 7.0 and later pg_dump to check the database
> version at startup and refuse to run if it's not the expected value.
>
> A downside is that a pg_dump might refuse to dump a DB that it actually
> would work with; that could be a pain in the neck, particularly in
> development scenarios where you might not have kept the previous
> compilation of pg_dump lying around. Yet I think I prefer that to the
> risk of an insidious incompatibility that causes pg_dump to run without
> complaint yet generate a bogus dump.
>
> Comments anyone?

It's a great idea and later down the road the versioning information
could be used to determine if it's actually possible to pg_dump
with a certain version, ie the pg_dump program can report its
version number to postgresql and postgresql can reply if it thinks
it's compatible with the version of pg_dump being used.

--
-Alfred Perlstein - [bright(at)wintelcom(dot)net|alfred(at)freebsd(dot)org]
"I have the heart of a child; I keep it in a jar on my desk."