> I tried to delete the user from the pg_user but couldnt. This username is
> being duplicated so we have the same 2 records.
>
> What is the cause ? Is it due to memory or wrong configuration?
Maybe it's an index corruption issue.
Try reindexing the pg_shadow table, based on the instructions here:
http://www.postgresql.org/docs/7.3/static/sql-reindex.html
Chris