| From: | David Steele <david(at)pgmasters(dot)net> |
|---|---|
| To: | Hironobu SUZUKI <hironobu(at)interdb(dot)jp> |
| Cc: | Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>, Andres Freund <andres(at)anarazel(dot)de>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
| Subject: | Re: Re: pgbench - add pseudo-random permutation function |
| Date: | 2019-03-21 17:27:49 |
| Message-ID: | be567349-f2ea-436f-faf0-bb5cc3b01c4a@pgmasters.net |
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| Lists: | pgsql-hackers |
Hi Hironobu,
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,
--
-David
david(at)pgmasters(dot)net
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