I have a serious problem with hanging backends.:SELECT waiting

Hi,

I have a serious problem with hanging backends.
This is wat I get from ps ->
postgres 23507 22794  0 13:33 ?        00:00:09
/usr/local/pgsql/bin/postgres 1.1.3.123 postgres bts01 SELECT waiting


This blocks all the other clients.   (ODBC call failed)

The situation

-  PostgreSQL 6.4.2 on i686-pc-linux-gnu, compiled by gcc 2.7.2.
(SlackWare)
-  30  Access 2000 clients connecting through 6.40.00.06 ODBC driver 

-   ODBC connections error's
       ->   CONN ERROR: func=SQLGetConnectOption,         desc='fOption=30002', errnum=205, errmsg='Unknown connect
option(Get)'
 

------------------------------------------------------------               henv=144902176, conn=144863832, status=0,
num_stmts=16            so        ck=144902128, stmts=144902048, lobj_type=-999
 

----------------SocketInfo-------------------------------            socket=-1, reverse=0, errornumber=0,
errormsg='(NULL)'           buffer_in=144870304, buffer_out=144874408            buffer_filled_in=0,
buffer_filled_out=0,buffer_read_in=0
 
             CONN ERROR: func=SQLSetConnectOption,             desc='fOption=30002, vParam=143791720', errnum=205,
errmsg='Unknownconnect option (Set)'
 

------------------------------------------------------------            henv=144902176, conn=144863832, status=0,
num_stmts=16             sock=144902128, stmts=144902048, lobj_type=-999
 

----------------SocketInfo-------------------------------             socket=-1, reverse=0, errornumber=0,
errormsg='(NULL)'            buffer_in=144870304, buffer_out=144874408             buffer_filled_in=0,
buffer_filled_out=0,            buffer_read_in=0
 

-  In de server-log I found that the access-application wants to
connect with the user Admin   then we get FATAL 1 : user Admin not in pg_shadow
But in the connection properties the user postgres is set.      This (connection with user Admin) seems to have started
withthe conversion 97 -> 2000
 
I've added the user, this error was gone, but some of the jobs
are admin owned other postgres
-  I had problems before with the MaxBackendIdI've rebuild with MaxBackendId set to 128  and started the     postmaster
with-B 256 parameter.This was because of the message "cache invalidation         initialization failed"     So this was
solved,or is
 

-  In the loggings the SELECT waiting jobs hang on ProcessQuery and
the other InitPostgres fail.

- vacuum verbose analyze doen't seem to report errors

- debug higher then 4 is not usable (2 gig in 10 minutes)


In which direction do I have to search?       Can there be data corruption without being reported?       Can it be
solvedwith a pg_dump file, destroydb, createdb,     psql -e file ?  (Not done already -> production machine)       Is
ourversion to old -> should an upgrade help?       .... ?        
 

Thanks,

Jeroen Ryckeboer