BUG #2538: Hang on insert/select

The following bug has been logged online:

Bug reference:      2538
Logged by:          John Lyssy
Email address:      jlyssy@charter.net
PostgreSQL version: 8.1.4
Operating system:   Windows 2003 Server
Description:        Hang on insert/select
Details:

Client application hangs on doing insert and/or select statement

2006-07-18 08:13:31 ERROR:  duplicate key violates unique constraint
"document_addrbook_xref_pkey"
2006-07-18 08:13:31 ERROR:  duplicate key violates unique constraint
"document_addrbook_xref_pkey"
2006-07-18 08:13:31 ERROR:  duplicate key violates unique constraint
"document_addrbook_xref_pkey"
2006-07-18 08:13:31 ERROR:  duplicate key violates unique constraint
"document_addrbook_xref_pkey"

I use insert statements to reload the same datafile and use the primary key
constraint to drop any already loaded data (e.g. I want the db constraint to
ignore inserts), after running for a few hours the client application hangs.
There are other php scripts importing data into other databases. I cancel
the hung insert command and the script starts working. I made a modification
to an import php script and want to verify that I have processed all data.