Re: SELECT .. FOR UPDATE: find out who locked a row

Greetings Melvin,

* Melvin Davidson (melvin6925(at)gmail(dot)com) wrote:
> On Thu, Mar 15, 2018 at 10:14 PM, Stephen Frost <sfrost(at)snowman(dot)net> wrote:
> > Changes will continue to be made between major versions of PostgreSQL
> > when they're deemed necessary; I'd suggest those applications be
> > prepared to adjust on a per-major-version basis when future changes
> > happen. We do have quite a bit of discussion about changes which are
> > made and they are not done so without good justification, but they can
> > and do happen.
>
> Yes, Stephen, I certainly understand making changes to system catalogs
> _when necessary_.
> That being said, the first change was the renaming of pid to procpid in
> pg_stat_activity.
> However, I contend that was more because someone felt that it was more to
> make the column names
> consistent across catalogs, rather than necessity. Care should be taken to
> consider the need and
> effect of changing EXISTING system columns. It may have been a mistake in
> originally naming it,
> but it was certainly working and not causing any problems at the time.

As mentioned earlier, care is taken when considering the need and effect
of changing existing system columns, but it can, and will, happen, and
therefore applications should be designed to cope with such changes
gracefully when they happen and tested thoroughly on each new major
version of PostgreSQL.

Thanks!

Stephen