Re: sortsupport for text

On 20 June 2012 15:10, Greg Stark <stark@mit.edu> wrote:
> On Sun, Jun 17, 2012 at 9:26 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> The trick for hashing such datatypes is to be able to guarantee that
>> "equal" values hash to the same hash code, which is typically possible
>> as long as you know the equality rules well enough.  We could possibly
>> do that for text with pure-strcoll equality if we knew all the details
>> of what strcoll would consider "equal", but we do not.
>
> It occurs to me that strxfrm would answer this question. If we made
> the hash function hash the result of strxfrm then we could make
> equality use strcoll and not fall back to strcmp.

What about per-column collations?

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