Thanks Antoine, I was using the test more for educational purposes but Brion's poist is a good reminder not to use page_random for any serious sampling purpose
G Giovanni Luca Ciampaglia ✎ 919 E 10th ∙ Bloomington 47408 IN ∙ USA ☞ http://www.glciampaglia.com/ ✆ +1 812 855-7261 ✉ [email protected] 2014-11-12 4:00 GMT-05:00 Antoine Musso <[email protected]>: > Le 11/11/2014 14:36, Brad Jorsch (Anomie) a écrit : > > On Tue, Nov 11, 2014 at 1:02 AM, Giovanni Luca Ciampaglia > <snip> > > > Drawing a list of random titles with page_random takes more than a > > > minute! > > > > > > Because you're doing it wrong. "page_random > rand()" evaluates rand() > > *for each row*. Since it's nowhere near constant, it can't use an index. > <snip> > > Hello, > > Grabbing random pages is a bit of madness which has long confused > people. Brion Vibber wrote a nice explanations a few years ago that > gives a good overview: > > https://brionv.com/log/2007/11/22/random-tests/ > > -- > Antoine "hashar" Musso > > > _______________________________________________ > Labs-l mailing list > [email protected] > https://lists.wikimedia.org/mailman/listinfo/labs-l >
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