Обсуждение: types for C function composites

In a backend C function, is there any way to get the type (Probably
via TupleDesc)  of a passed in composite type?  I'm trying to build a
generic function that does not assume the types of the composite
fields...I take it this might not be possible.

merlin

"Merlin Moncure" <mmoncure@gmail.com> writes:
> In a backend C function, is there any way to get the type (Probably
> via TupleDesc)  of a passed in composite type?

Sure.  The canonical example is record_out().

            regards, tom lane

A question came up on the Slony-I list (quite a while ago, but that's
another story!) as to the handling of floating point values.

The user is concerned about whether FP values are faithfully
replicated.  I commented that the issue will be identical to that of
the handling of data in pg_dump; if Slony-I creates differences by
rounding things, so also would pg_dump.

In the interests of personal laziness ;-), I'll throw the question to
this list: how may we expect the imprecisions of FP affect text-based
database dumps, if at all?
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Chris Browne <cbbrowne@acm.org> writes:
> In the interests of personal laziness ;-), I'll throw the question to
> this list: how may we expect the imprecisions of FP affect text-based
> database dumps, if at all?

If the platform's float I/O routines conform fully to spec, you can
expect FP values to reload exactly.  We dump them with a couple of
"extra" digits of precision to make this possible.

            regards, tom lane