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Re: Storing large strings for future equality checks

Cross-posted to 3 groups.

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On 6/8/2011 10:58 PM, Willem wrote:
> markspace wrote:
> ) On 6/8/2011 9:35 AM, Abu Yahya wrote:
> )>  I considered using an SHA-512 hash of these strings and storing them in
> )>  the database. However, while these will save on storage space, it will
> )>  take time to do the hashing before comparing an incoming string. So I'm
> )>  still wasting time. (Collisions due to hashing will not be a problem,
> )>  since an occasional false positive will not be fatal for my application).
> )
> ) You have to store the whole string.  Even if the SHA-512 hash codes are
> ) equal, it could be that the strings are different.  You'll have to
> ) eventually compare the raw string, even if the SHA is used as a
> ) quick-out case.
>
> No he doesn't.  Read again.  Especially the last bit between parentheses.
>

Yeah, it seems he missed that last part or read it incorrectly.

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Thread

Storing large strings for future equality checks Abu Yahya <abu_yahya@invalid.com> - 2011-06-08 22:05 +0530
  Re: Storing large strings for future equality checks markspace <-@.> - 2011-06-08 09:49 -0700
    Re: Storing large strings for future equality checks Willem <willem@toad.stack.nl> - 2011-06-08 17:28 +0000
      Re: Storing large strings for future equality checks Abu Yahya <abu_yahya@invalid.com> - 2011-06-08 23:45 +0530
    Re: Storing large strings for future equality checks Abu Yahya <abu_yahya@invalid.com> - 2011-06-08 23:45 +0530
  Re: Storing large strings for future equality checks David Kerber <dkerber@WarrenRogersAssociates.invalid> - 2011-06-08 12:58 -0400
    Re: Storing large strings for future equality checks Abu Yahya <abu_yahya@invalid.com> - 2011-06-08 23:49 +0530
    Re: Storing large strings for future equality checks Lothar Kimmeringer <news200709@kimmeringer.de> - 2011-06-08 20:31 +0200
      Re: Storing large strings for future equality checks Harry Tuttle <OTPXDAJCSJVU@spammotel.com> - 2011-06-09 10:50 +0200
        Re: Storing large strings for future equality checks bugbear <bugbear@trim_papermule.co.uk_trim> - 2011-06-09 11:44 +0100
      Re: Storing large strings for future equality checks Harry Tuttle <OTPXDAJCSJVU@spammotel.com> - 2011-06-10 10:15 +0200
  Re: Storing large strings for future equality checks Gene Wirchenko <genew@ocis.net> - 2011-06-08 11:07 -0700
    Re: Storing large strings for future equality checks Abu Yahya <abu_yahya@invalid.com> - 2011-06-08 23:58 +0530
    Re: Storing large strings for future equality checks Hallvard B Furuseth <h.b.furuseth@usit.uio.no> - 2011-06-09 12:38 +0200
    Re: Storing large strings for future equality checks Michael Wojcik <mwojcik@newsguy.com> - 2011-06-09 17:32 -0400
      Re: Storing large strings for future equality checks bugbear <bugbear@trim_papermule.co.uk_trim> - 2011-06-10 10:51 +0100
  Re: Storing large strings for future equality checks Lothar Kimmeringer <news200709@kimmeringer.de> - 2011-06-08 20:28 +0200
    Re: Storing large strings for future equality checks Martin Gregorie <martin@address-in-sig.invalid> - 2011-06-08 22:02 +0000
  Re: Storing large strings for future equality checks rossum <rossum48@coldmail.com> - 2011-06-08 21:38 +0100
  Re: Storing large strings for future equality checks Robert Klemme <shortcutter@googlemail.com> - 2011-06-08 23:20 +0200
  Re: Storing large strings for future equality checks Tom Anderson <twic@urchin.earth.li> - 2011-06-08 23:02 +0100
  Re: Storing large strings for future equality checks Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-09 15:01 -0700

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