Re: bug report: pg_dump does not use CASCADE in DROP

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Once pg_dump starts using the dependency information, it seems it could
> > do the drops in the proper order, and when it detects
> > mutually-dependent tables, it can use a single DROP CASCADE to remove
> > them all --- seems like that is a TODO.
>
> You missed my point entirely. What if DROP CASCADE causes a drop of a
> table that did not even exist in the source database, but was added in
> the target after the initial data load? It seems unlikely that that is
> desirable behavior for pg_restore.
>
> The correct use of dependency information would be to sort the DROPs
> into an order that should succeed *without* CASCADE. (This will
> actually happen for free AIUI, once pg_dump uses dependency info fully.
> DROPping in the reverse of a safe creation order should work.)

Right, but how do you drop two tables that REFERENCE each other? Seems
you have to use CASCADE in that case.

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