Re: describe objects, as in pg_depend

Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> Excerpts from Tom Lane's message of mi nov 17 12:20:06 -0300 2010:
>> What's the point of the InvalidOid check?

> If the check is not there, the calling query will have to prevent the
> function from being called on rows having OID=0 in pg_depend. (These
> rows show up in the catalog for pinned objects).

Hmm. It would be good to document that motivation somewhere. Also,
for my own taste it would be better to do

/* for "pinned" items in pg_depend, return null */
if (!OidIsValid(catalogId))
PG_RETURN_NULL();

... straight line code here ...

rather than leave the reader wondering whether there are any other cases
where the function is intended to return null.

Oh, one other gripe: probably better to name it pg_describe_object.

regards, tom lane