Re: Hash support for arrays

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От Robert Haas
Тема Re: Hash support for arrays
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Msg-id 7882D015-FE82-4C9F-94DF-C75F95E1B055@gmail.com
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Ответ на Re: Hash support for arrays  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: Hash support for arrays  (Tom Lane <tgl@sss.pgh.pa.us>)
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On Nov 2, 2010, at 1:42 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> However, this is largely beside the point, because that theory, as well
> as the Java code you're arguing from, has to do with the initial hashing
> of a raw sequence of input items.  Not with combining some existing hash
> values.  The rotate-and-xor method I suggested for that is borrowed
> exactly from section 6.4 of Knuth (page 512, in the first edition of
> volume 3).

It seems undesirable to me to have a situation where transposing two array elements doesn't change the hash value.  But
Ijust work here. 

...Robert

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