ERROR: cache lookup failed for relation 17442

Hi All,

I've been getting these errors ("ERROR: cache lookup failed for
relation 17442") in my logs for a while now. It originally seemed
like a hardware problem, however now we getting them pretty consistently
on a couple servers. I've scalled down the schema to the one table and
the function involved and included a code snipet to make a bunch of
connections and loop around calling the same function. It usually
takes 100-2000 iterations before these messages start appearing in the
log. I've also included the original function, this takes 10,000
iterations for the error to start showing. I should note, we've been
getting these erros since version 7, this is the first time they were
reproducable..

With the original function, the log messages were slightly different and
usually caused the server to reset:
i.e.
ERROR: type "t" already exists
ERROR: duplicate key violates unique constraint
"pg_type_typname_nsp_index"
ERROR: duplicate key violates unique constraint
"pg_type_typname_nsp_index"
ERROR: duplicate key violates unique constraint
"pg_type_typname_nsp_index"
CONTEXT: SQL statement "create temp table tmp_children ( uniqid bigint,
memberid bigint, membertype varchar(50), ownerid smallint, tag
varchar(50), level int4 )"
PL/pgSQL function "fngetcompositeids2" line 14 at SQL statement
ERROR: duplicate key violates unique constraint
"pg_type_typname_nsp_index"
ERROR: cache lookup failed for type 2449707570
FATAL: cache lookup failed for type 2449707570

Environment info: Postgres v8, suse linix with latest kernal patches,
filesystem: reiserfs.

Please let me know if you need anymore information. No data is need,
just the schema included.

Thanks
Michael