Thread: TupleDesc refcounting, again
Those of you with long memories may recall a discussion back in January about reference-counting TupleDescs retrieved by lookup_rowtype_tupdesc(). I didn't like the patch Neil Conway developed for this, so I'm on the hook to find a better answer before 8.2 comes out. I haven't forgotten ... but I was reminded of it while looking at the performance issue pointed out by Marc Orgassa here: http://archives.postgresql.org/pgsql-novice/2006-05/msg00153.php If oprofile is to be trusted, Marc's second example spends something close to forty percent of its runtime in CreateTupleDescCopy() operations (including the subsidiary memcpy() calls). Yikes. A reference-counting mechanism would have to be cheaper than that. So I'll try to bubble this issue up to the top of the to-do queue again... regards, tom lane