Re: dump/restore results in duplicate key violation with 7.4.6.

Update.

After Tom mentioned that my issue might be locale related I ran
pg_controldata on both servers.

On gentoo, LC_COLLATE and LC_CTYPE are set to C locale. On Redhat they
are set to en_US.UTF-8.

I re-ran initdb on Redhat with the --locale=C param, and performed the
import again. This time all data imported correctly.

That is great, as it enables me to move forward, but there's still a
couple open questions:

1) I don't understand why a difference in locale should cause a
duplicate key error, especially when both databases were created using
'UNICODE' encoding. Is this valid behavior or a postgres bug?

2) According to the docs [1], locale is set at initdb time. The redhat
machine is a production server and has other databases running for other
applications. I could do a dump of all data, then initdb, then import
data, but it occurs to me that I might run into a similar "duplicate
key" error (or other import strangeness) in one of the other databases.
Can anyone shed more light on the implications of moving data from
en_US.UTF-8 locale to C locale?

regards,

Dan Libby

[1] http://www.postgresql.org/docs/7.4/static/charset.html