Hi, There are some things about the life cycle of the common TupleDesc that I'm not 100% sure about.
1. In general, if you get one from relcache or typcache, it is reference-counted, right? 2. The only exception I know of is if you ask the typcache for a blessed one (RECORD+typmod), and it is found in the shared-memory cache. It is not refcounted then. If it is found only locally, it is refcounted. 3. Is that shared case the only way you could see a non-refcounted TupleDesc handed to you by the typcache? 4. How long can such a non-refcounted TupleDesc from the typcache be counted on to live? There is a comment in expandedrecord.c: "It it's not refcounted, just assume it will outlive the expanded object." That sounds like confidence, but is it confidence in the longevity of shared TupleDescs, or in the fleeting lives of expanded records? The same comment says "(This can happen for shared record types, for instance.)" Does the "for instance" mean there are now, or just in future might be, other cases where the typcache hands you a non-refcounted TupleDesc? 5. When a constructed TupleDesc is blessed, the copy placed in the cache by assign_record_type_typmod is born with a refcount of 1. Assuming every later user of that TupleDesc plays nicely with balanced pin and release, what event(s), if any, could ever occur to decrease that initial 1 to 0? Thanks for any help getting these points straight! Regards, -Chap
