| From: | Peter Geoghegan <pg(at)heroku(dot)com> |
|---|---|
| To: | Claudio Freire <klaussfreire(at)gmail(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>, Stephen Frost <sfrost(at)snowman(dot)net>, Greg Stark <stark(at)mit(dot)edu>, Noah Misch <noah(at)leadboat(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Thom Brown <thom(at)linux(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: B-Tree support function number 3 (strxfrm() optimization) |
| Date: | 2014-07-14 18:17:09 |
| Message-ID: | CAM3SWZRLjA=+RZSbLPX9k=kjsgYwxypU_ADYm0vLTfSDh4VrYA@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Mon, Jul 14, 2014 at 11:03 AM, Claudio Freire <klaussfreire(at)gmail(dot)com> wrote:
> Are those numbers measured on MAC's strxfrm?
>
> That was the one with suboptimal entropy on the first 8 bytes.
No, they're from a Linux system which uses glibc 2.19. The
optimization will simply be not used on implementations that don't
meet a certain standard (see my AC_TRY_RUN test program). I'm
reasonably confident that that test program will pass on most systems.
Just not Mac OSX. The optimization is never used on Windows and 32-bit
systems for other reasons.
--
Peter Geoghegan
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