Re: RFC: Restructuring pg_aggregate

Christopher Kings-Lynne wrote:
> > If the client has to bear the some part, isn't the invisible
> > column approach much simpler ?
> >
> > I've put a pretty much time into DROP COLUMN feature but
> > I am really disappointed to see the comments in this thread.
> > What DROP COLUMN has brought me seems only a waste of time.
>
> I kind of agree with Hiroshi here. All I want to be able to do is drop
> columns from my tables, and reclaim the space. I've got all sorts of
> production tables with columns just sitting there doing nothing, awaiting
> the time that I can happily drop them. It seems to me that whatever we do
> will require some kind of client breakage.

Actually, what we need to do to reclaim space is to enable table
recreation without the column, now that we have relfilenode for file
renaming. It isn't hard to do, but no one has focused on it. I want to
focus on it, but have not had the time, obviously, and would be very
excited to assist someone else.

Hiroshi's fine idea of marking certain columns as unused would not have
reclaimed the missing space, just as my idea of physical/logical column
distinction would not reclaim the space either. Again, my
physical/logical idea is more for fixing other problems and
optimization, not DROP COLUMN.

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