Re: duplicate key violated errors

dinesh <dinesh@mongonet.net> writes:
> I have a table, which has over 3 million rows. We have both a unique
> constraint ( which creates implicit index) as well as a regular unique
> index on the same column. We had to put the unique constraint because
> duplicate values
> were getting inserted to the table in spite of the regular unique index
> on the column.

That sounds awfully fishy.  We have not heard of unique indexes failing
to enforce the constraint in quite some time.

What's the data type of the column?  A possible explanation for this
kind of issue is a broken comparison function for the particular data
type.

> We run  postgresql 8.2.5

That's two years out of date, and the list of bugs fixed since then is
quite extensive.  A quick scan through the release notes doesn't show
any obviously-related bugs, but it would still be worth your while to
update to 8.2.latest and then reindex to see if the problem goes away.

            regards, tom lane