Re: About adding a new filed to a struct in primnodes.h - Mailing list pgsql-hackers

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 -- for
precisely this reason.