Unique Index - Mailing list pgsql-general

Hi,

i have a unique index on a table over multiple columns. If now one of
the records has a null value in one of the indexed columns i can insert
the same record multiple times.

Is this a problem within postgres or expected?

Example:

index unique, btree (colA, colB, colC);

would still allow me to insert

AAAA, ,CCCC
AAAA, ,CCCC


Thanks for any help on that.
A