Re: Centralizing protective copying of utility statements

On Thu, Jun 17, 2021 at 01:03:29PM -0400, Tom Lane wrote:
> 
> Here's a v2 that does it like that.  In this formulation, we're
> basically hoisting the responsibility for doing copyObject up into
> ProcessUtility from its direct children, which seems like a clearer
> way of thinking about what has to change.

I agree that forcing an API break is better.  Just a nit:

+ *    readOnlyTree: treat pstmt's node tree as read-only

Maybe it's because I'm not a native english speaker, or because it's quite
late here, but I don't find "treat as read-only" really clear.  I don't have a
concise better wording to suggest.

> Still thinking about which way to fix it in the back branches.

I'm +0.5 for a narrow fix, due to the possibility of unspotted similar problem
vs possibility of performance regression ratio.