> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > OK, code backed out. If the storage formats are the same, doesn't that
> > make them binary compatibile.
>
> No, because one allows nulls and the other doesn't. If you disregard
> what are legal values and what aren't, then every pair of varlena
> datatypes we have could be called "binary compatible".
>
> More to the point, though, why *should* they be marked binary
> compatible? I saw no compelling reason advanced for it, and I can see a
> couple of compelling reasons not to. Every binary-compatible pairing is
> another hole in our type system, another opportunity for unexpected
> behavior. We shouldn't add them on whims. Especially we shouldn't add
> them for datatypes that aren't even of the same family. bytea isn't for
> storage of textual data, and so it makes little sense to allow
> application of textual operations to it.
I have no idea why the user wanted it. I suppose it was so he could
pass text/varchar to bytea and back again. Seems he has to convert it,
which makes sense about the NULLs.
--
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