Thread

Re: [PATCH] Proposal for HIDDEN/INVISIBLE column

Jaime Casanova <jcasanov@systemguards.com.ec> — 2021-10-14T15:38:56Z

On Thu, Oct 14, 2021 at 01:16:45PM +0200, Gilles Darold wrote:
> Hi,
> 
> 
> Here is a proposal to implement HIDDEN columns feature in PostgreSQL.
> 

Great! Actually I found this very useful, especially for those people
using big fields (geometry, files, large texts).

> The user defined columns are always visible in the PostgreSQL. If user
> wants to hide some column(s) from a SELECT * returned values then the
> hidden columns feature is useful. Hidden column can always be used and
> returned by explicitly referring it in the query.
> 
> I agree that views are done for that or that using a SELECT * is a bad
> practice

An a common one, even if we want to think otherwise. I have found that
in almost every customer I have the bad luck to get to see code or
SELECTs.

Not counting that sometimes we have columns for optimization like Dave
saved about hidden a ts_vector column.

Another use case I can think of is not covered in this patch, but it
could be (I hope!) or even if not I would like opinions on this idea. 
What about a boolean GUC log_hidden_column that throws a LOG message when 
a hidden column is used directly?

The intention is to mark a to-be-deleted column as HIDDEN and then check
the logs to understand if is still being used somewhere. I know systems
where they carry the baggage of deprecated columns only because they
don't know if some system is still using them.

I know this would be extending your original proposal, and understand if
you decide is not a first patch material. 

Anyway, a +1 to your proposal. 

-- 
Jaime Casanova
Director de Servicios Profesionales
SystemGuards - Consultores de PostgreSQL