Subject: Re: v18 virtual columns

From: Ron Johnson <[email-masked]>
Date: Thu, 20 Feb 2025 09:30:53 -0500

On Thu, Feb 20, 2025 at 8:07 AM Dominique Devienne <[email-masked]>
wrote:

> Hi. I've just read
> https://www.dbi-services.com/blog/postgresql-18-virtual-generated-columns/
>
> and I'm wondering whether there will be a way to ALTER existing STORED
> generated columns, to be virtual? W/o rewriting the whole table that is.
>

What about dropping the existing stored column then adding the new virtual
column?

You won't get any disk space saving for existing records, but it's not
going to rewrite the table.

-- 
Death to <Redacted>, and butter sauce.
Don't boil me, I'm still alive.
<Redacted> lobster!

---

From: Dominique Devienne <[email-masked]>
Date: Thu, 20 Feb 2025 15:33:57 +0100

> going to rewrite the table.

Didn't think of that, but yes, I think that would work.
They are GENERATED columns, so the values stored are derived data anyway,
indeed.

I also didn't know DROP COLUMN was smart enough not rewriting the column,
that's good.

Thanks, --DD