Your test are on the command line, not inside apache and thus more or less worthless.
As André clearly showed the issue is almost certainly with the way srand is being called inside apache Add a call to srand with something suitably random from time pid and maybe /dev/random INSIDE apache before generating your ‘random’ code The issue will almost certainly go away -- Clive Eisen GPG: 75056DD0 > On 17 May 2016, at 13:11, Vincent Veyron <vv.li...@wanadoo.fr> wrote: > > On Tue, 17 May 2016 10:16:43 +0200 > André Warnier <a...@ice-sa.com> wrote: >> >> I don't see above any signifiant difference in configuration between the >> servers, apart >> from the fact that the "faulty" server runs a 64-bit version of perl. > > Sorry : slightly digressive rant about the fact that every time I compare my > configs, I find some subtle differences. Should be getting into config > management tools, but that takes time too. > >> >> Now I also found this : >> http://rabexc.org/posts/randomizing-should-be-easy-right-oh >> >> I am not sure that I really understand this all the way down, but would this >> not be a >> suspect in a case where the behaviour seems different between one 64-bit >> machine, and a >> bunch of 32-bit ones ? > > Nope; same results on both types when running the script > >> >> This being said, it still looks to me as if the current code is flawed on >> *all* machines, >> and *will* repeat keys quite often. It just depends again on the exact >> sequence of >> requests hitting a specific Apache, and the other parameters I mentioned >> before. >> I still believe that the fact that it does not *seem* to happen, is just due >> to the >> inherent randomness of these other factors on the production machines. >> > > Well, I already posted a test with ab and 12 000 requests, so not sure about > the 'quite often' part? > > This is on the faulty one : > > xxxx@arsene:~$ perl -le '%h=();for (1..10_000_000) {my $session_id = join "", > map +(0..9,"a".."z","A".."Z")[rand(10+26*2)], > 1..32;$h{$session_id}=1};$v=keys %h; print $v' > 10000000 > > > -- > Bien à vous, Vincent Veyron > > https://libremen.com > Logiciels de gestion, libres
