ERROR: cache lookup failed for relation

Hi,

    Our database restarted sometime this morning and now the log is
reporting this error "ERROR: cache lookup failed for relation
2029055522".   I was able to isolate the sql statement that causes this
error, however,  I was only able to re-produce the error once and then
crashed the postmaster when trying to debug the process :(  Also, I
should note that when I reproduced the error, one psql sesssion caused
this error, while another psql session executing the same statement
worked fine.. Both were fresh ssessions.

This is the statement that gets executed.
LOG:  statement: select * into temp table t from
fnGetCompositeIds2(5825634844);

It seems to only happen with a routine that deals with temporary tables,
the function uses temp tables too.

Vacuum completes without errors, I've re-indexed all system tables and
user tables and postgresql was restarted.

Sorry about the lack of info, just checking to see if anyone has any
comments about how to track down this problem...  pg version is
"PostgreSQL 8.0.0beta3 on i686-pc-linux-gnu, compiled by GCC gcc (GCC)
3.4.2"

thanks
michael