Le 11 févr. 2018 à 21:03, Andres Freund écrivait : > > > On February 11, 2018 12:00:12 PM PST, Nicolas Paris <niparisco@xxxxxxxxx> wrote: > >> > That is true, but the question is how significant the overhead is. > >If > >> > it's 50% then reducing it would make perfect sense. If it's 1% then > >no > >> > one if going to be bothered by it. > >> > >> I think it's pretty clear that it's going to be way way much more > >than > >> 1%. > > > >Good news but not sure to anderstand why. > > I think you might have misunderstood my reply? I'm saying that going through PROGRAM will have significant overhead. I can't quite make sense of the rest of your reply otherwise? True, I misunderstood. Then I agree the computation overhead should be non-negligible. I have also the storage and network transfers overhead in mind: All those new formats are compressed; this is not true for current postgres BINARY format and obviously text based format. By experience, the binary format is 10 to 30% larger than the text one. On the contrary, an ORC file can be up to 10 times smaller than a text base format.
