Re: jsonb format is pessimal for toast compression

* Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
> Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > On Thu, Sep 25, 2014 at 02:39:37PM -0400, Tom Lane wrote:
> >> BTW, it seems like there is consensus that we ought to reorder the items
> >> in a jsonb object to have keys first and then values, independently of the
> >> other issues under discussion. This means we *will* be breaking on-disk
> >> compatibility with 9.4beta2, which means pg_upgrade will need to be taught
> >> to refuse an upgrade if the database contains any jsonb columns. Bruce,
> >> do you have time to crank out a patch for that?
>
> > Yes, I can do that easily. Tell me when you want it --- I just need a
> > catalog version number to trigger on.
>
> Done --- 201409291 is the cutover point.

Just to clarify- the commit bumped the catversion to 201409292, so
version <= 201409291 has the old format while version > 201409291 has
the new format. There was no 201409291, so I suppose it doesn't matter
too much, but technically 'version >= 201409291' wouldn't be accurate.

I'm guessing this all makes sense for how pg_upgrade works, but I found
it a bit surprising that the version mentioned as the cutover point
wasn't the catversion committed.

Thanks,

Stephen