Re: Theory of operation of collation patch - Mailing list pgsql-hackers

From Susanne Ebrecht
Subject Re: Theory of operation of collation patch
Date
Msg-id 4D764158.50303@2ndQuadrant.com
Whole thread Raw
In response to Theory of operation of collation patch  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Theory of operation of collation patch
List pgsql-hackers
On 07.03.2011 17:43, Tom Lane wrote:
> because two expressions that are equal() must necessarily have the same collation
> property.

Peter, Tom,

I am not able to see this.

If 'abc' == 'abc' is not collation depending at all. It is only
encoding depending.

Collation is only needed for upper(), lower() and sorting.
Means it tells if e.g. upper('i') will get Y or I.
It tells if the German s-umlaut will be sorted together with 's' or 
after 'z'.

Btw. the follows on implementing collations will be different -
and I hope Peter is aware of it.

My experience is that a huge follow will be that users will complain 
that the
sorting isn't correct even when it is correct.

Susanne

-- 
Susanne Ebrecht - 2ndQuadrant
PostgreSQL Development, 24x7 Support, Training and Services
www.2ndQuadrant.com



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