On 12/14/21 20:02, Tom Lane wrote: > The API contract for lookup_rowtype_tupdesc specifies that you must "call > ReleaseTupleDesc or DecrTupleDescRefCount when done using the tupdesc". > It's safe to assume that the tupdesc will stick around as long as you > haven't done that.
I think what threw me was having a function whose API contract mentions reference counts, but that sometimes gives me things that don't have them. But I guess, making the between-the-lines of the contract explicit, if lookup_rowtype_tupdesc is contracted to give me a tupdesc that sticks around for as long as I haven't called ReleaseTupleDesc, and it sometimes elects to give me one for which ReleaseTupleDesc is a no-op, the contract is still that the thing sticks around for (at least) as long as I haven't done that. Cool. :) Oh, hmm, maybe one thing in that API comment ought to be changed. It says I must call ReleaseTupleDesc *or* DecrTupleDescRefCount. Maybe that dates from before the shared registry? ReleaseTupleDesc is safe, but anybody who uses DecrTupleDescRefCount on a lookup_rowtype_tupdesc result could be in for an assertion failure if a non-refcounted tupdesc is returned. Regards, -Chap
