Re: pgbench - add pseudo-random permutation function
От | Fabien COELHO |
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Тема | Re: pgbench - add pseudo-random permutation function |
Дата | |
Msg-id | alpine.DEB.2.21.1905231641450.28482@lancre обсуждение исходный текст |
Ответ на | Re: pgbench - add pseudo-random permutation function (Hironobu SUZUKI <hironobu@interdb.jp>) |
Ответы |
Re: pgbench - add pseudo-random permutation function
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Список | pgsql-hackers |
Hello Hironobu-san, Here is a v15 which is a rebase, plus a large simplification of the modmul function if an int128 type is available, which is probably always… Could you have a look and possibly revalidate? > Sorry for the late reply. I reviewed this patch. > > Function nbits(), which was previously discussed, has been simplified by > using the function pg_popcount64(). > > By adding the mathematical explanation, it has been easier to understand the > operation of this function. > > I believe that these improvements will have a positive impact on maintenance. > > The patch could be applied successfully and the tests passed without > problems. > > So, I think the latest patch is fine. > > > Best regards, > > > >> On 3/3/19 12:55 PM, Fabien COELHO wrote: >>> >>>> Indeed, the patch needs a rebase & conflit resolution. I'll do it. Later. >>> >>> Here is an update: >>> >>> - take advantage of pg_bitutils (although I noted that the "slow" >>> popcount there could be speeded-up and shorten with a bitwise operator >>> implementation that I just removed from pgbench). >>> >>> - add comments about the bijective transformations in the code. >>> >>> As already stated, this function makes sense for people who want to test >>> performance with pgbench using non uniform rands. If you do not want to do >>> that, you will probably find the function pretty useless. I can't help it. >>> >>> Also, non uniform rands is also a way to test pg lock contention behavior. >> >> You have signed up as a reviewer for this patch. Do you know when you'll >> have time to do the review? >> >> Regards, > > -- Fabien Coelho - CRI, MINES ParisTech
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