References to them persist in system catalogs. Otherwise, dropping a column would require rewriting every row in the table.
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Scott Ribe
scott_ribe(at)elevated-dev(dot)com
https://www.linkedin.com/in/scottribe/
> On Jun 6, 2018, at 12:43 PM, Wells Oliver <wells(dot)oliver(at)gmail(dot)com> wrote:
>
> Just curious then, in what meaningful way do dropped columns persist, what are the reasons?
>