> > I'm drawing a blank on trivial candidate uses for preadv(), without > > infrastructure from later patches. > > Can't immediately think of something either.
This might be not that trivial , but maybe acquire_sample_rows() from analyze.c ? Please note however there's patch https://www.postgresql.org/message-id/20201109180644.GJ16415%40tamriel.snowman.net ( https://commitfest.postgresql.org/30/2799/ ) for adding fadvise, but maybe those two could be even combined so you would be doing e.g. 16x fadvise() and then grab 8 pages in one preadv() call ? I'm find unlikely however that preadv give any additional performance benefit there after having fadvise, but clearly a potential place to test. -J.
