Re: [HACKERS] Re: ALTER TABLE DROP COLUMN

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> Bruce Momjian writes:
> 
> > You can exclusively lock the table, then do a heap_getnext() scan over
> > the entire table, remove the dropped column, do a heap_insert(), then a
> > heap_delete() on the current tuple,
> 
> Wow, that almost seems to easy to be true. I never thought that having
> tuples of different structures in the table at the same time would be
> possible. If so then I don't see a reason why this would be too hard to
> do.

If the transaction is not committed, I don't think anything actually
reads the tuple columns, so you are safe.

-- 
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