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Re: Storing large strings for future equality checks

From Abu Yahya <abu_yahya@invalid.com>
Newsgroups comp.lang.java.programmer, comp.programming, comp.lang.java.databases
Subject Re: Storing large strings for future equality checks
Date 2011-06-08 23:58 +0530
Organization Aioe.org NNTP Server
Message-ID <isof0m$rcp$1@speranza.aioe.org> (permalink)
References <iso8cm$a80$1@speranza.aioe.org> <g6evu6t9847r0g5u2nj17aj61gsktspb93@4ax.com>

Cross-posted to 3 groups.

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On 6/8/2011 11:37 PM, Gene Wirchenko wrote:
> On Wed, 08 Jun 2011 22:05:30 +0530, Abu Yahya<abu_yahya@invalid.com>
> 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).
>
>       What does "occasional" mean?
>

The application will be doing some probabilistic evaluation using the 
data it is storing, and needs to be fairly close to the actual /most/ of 
the time. Because it would anyway be impossible to be correct 100% of 
the time, using a wrong value for a particular piece of input data will 
not matter, provided it does not happen too often. (In my text above, 
"rare" would have been a better choice of word than "occasional")

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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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