Re: About adding a new filed to a struct in primnodes.h

On Tue, Nov 24, 2020 at 11:11 PM Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
wrote:

> On 2020-Nov-24, Andy Fan wrote:
>
> > then we modified the copy/read/out functions for this node. In
> > _readFuncExpr,
> > we probably add something like
>
> > [ ... ]
>
> > Then we will get a compatible issue if we create a view with the node in
> > the older version and access the view with the new binary.
>
> When nodes are modified, you have to increment CATALOG_VERSION_NO which
> makes the new code incompatible with a datadir previously created

Thank you Alvaro. I just think this issue can be avoided without causing
the incompatible issue. IIUC, after the new binary isn't compatible with
the datadir, the user has to dump/restore the whole database or use
pg_upgrade. It is kind of extra work.

-- for precisely this reason.
>

I probably didn't get the real point of this, sorry about that.

--
Best Regards
Andy Fan