I wrote: > Hmm, is that actually true? There's no more reason to think a tuple > in a temp table is old enough to be visible to all other sessions > than one in any other table. It could be all right if we had a > special-case rule for setting all-visible in temp tables. Which > indeed I thought we had, but I can't find any evidence of that in > vacuumlazy.c, nor did a trawl of the commit log turn up anything > promising. Am I just looking in the wrong place?
Ah, never mind that --- I must be looking in the wrong place. Direct experimentation proves that VACUUM will set all-visible bits for temp tables even in the presence of concurrent transactions. regards, tom lane