Re: pgsql: Prevent concurrent SimpleLruTruncate() for any given SLRU.

On Sat, Aug 15, 2020 at 04:39:05PM -0400, Tom Lane wrote:
> Noah Misch <noah@leadboat.com> writes:
> > Prevent concurrent SimpleLruTruncate() for any given SLRU.
> 
> I find it fairly scary that you've changed enum LockTagType in the
> back branches.  Are we quite certain that no extensions have compiled-in
> values of that enum?
> 
> Safer from an ABI standpoint would be to add the new value at the end,
> at least in the back branches.

Yeah, that was negligent.  Several PGXN modules do refer to locktags.  I'll
move it.