Re: Change sort order on UUIDs?

Tom Lane wrote:
> "Robert Wojciechowski" <robertw@expressyard.com> writes:
>> I've been testing the new UUID functionality in 8.3dev and noticed that
>> UUIDs are sorted using memcmp in their default in-memory layout,
>> ...
>> When done that way, you're going to see a lot of index B-tree
>> fragmentation with even DCE 1.1 (ISO/IEC 11578:1996) time based UUIDs,
> 
> This claim seems like nonsense.  Btrees don't care about the ordering
> details of what they index.

I believe he means that with his modified comparison function, when 
inserting a series of UUIDs with increasing time-fields, the index keys 
are always inserted to the rightmost page, which gives a more tightly 
packed index than scattered inserts all-around the index.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com