strange sql system error 901 has cropped up

I have  a curious case.
We have V4R5 running ok for the past 2 years. All the programs were also
running ok since then.
4 days back, an IPL and a complete backup was taken ( thats a regular
affair on a monthly basis). Everything was normal during the backup and IPL
procedure.

But few of the SQL statements in a few programs now has started failing now
and then with SQLCODE 901.

Interestingly,all these SQL statements are having subselects. At times ,
the SQL runs successfully and at times in another session, it fails.I am
giving the SQL statement.
SELECT ID_PROCSPC
                   FROM FPPCCPDLDB/V_PPRCCHRT
WHERE  CD_TYPRCSP = 'A'      AND
PROC_CHTNO IN (SELECT  PROC_CHTNO FROM FPPCCPDLDB/V_PTDCPRLN
               WHERE PROC_CHTNO LIKE '%S'   AND
               TDC_NO IN (SELECT TDC_NO FROM FPPCCPDLDB/V_PTDCNO
                        WHERE STL_QLTYCD = 'T01018'))

The dspjoblog when query is successful is as
follows.................................................
CONNECT to relational database AS40017 completed.
Current connection is to relational database AS40017.
Current connection is to relational database AS40017.
Unable to retrieve query options file.
Unable to retrieve query options file.
Subselects processed as join query.
Selection fields mapped to different attributes.
All access paths were considered for file V_PTDCPRLN.
Access path built from keyed file I_PTDCPRLN.
File V_PPRCCHRT processed in join position 1.
File V_PTDCPRLN processed in join position 2.
File V_PTDCNO processed in join position 3.
ODP created.
Blocking used for query.
Connection to relational database AS40017 ended.
SQL cursors closed.

dspjoblog when the query fails is as follows :
CONNECT to relational database AS40017 completed.
Current connection is to relational database AS40017.
Current connection is to relational database AS40017.
Unable to retrieve query options file.
Unable to retrieve query options file.
Invalid value in floating-point instruction.
Internal failure occurred in query processor.
SQL system error.
Connection to relational database AS40017 ended.
SQL cursors closed.

Message ID . . . . . . :   MCH1209       Severity . . . . . . . :   40
Message type . . . . . :   Escape
Date sent  . . . . . . :   25/03/03      Time sent  . . . . . . :
09:36:04
Message . . . . :   Invalid value in floating-point instruction.
Cause . . . . . :   The floating-point operation requested cannot be done.
  This is caused by values which are not valid for this operation. Frequent
  causes of this condition include:
    -- Addition or subtraction of infinity with infinity.
    -- Multiplication of zero times infinity.
    -- Division of zero by zero.
    -- Division of infinity by infinity.
Recovery  . . . :   Correct the invalid value in the floating-point
  instruction.
 Message ID . . . . . . :   CPF4204       Severity . . . . . . . :   50
 Message type . . . . . :   Escape
 Date sent  . . . . . . :   25/03/03      Time sent  . . . . . . :
09:36:04
 Message . . . . :   Internal failure occurred in query processor.
 Cause . . . . . :   A system failure has occurred in the query processor
   program.  The query definition template number is 1.
 Recovery  . . . :   See the low-level messages.  Correct any errors and
try
   your request again.  If the problem continues, report the problem
(ANZPRB
   command).


IBM people here have no clue about it. Have any of u got a solution ? What
is the cause ? We have got the latest pfts already installed on the
machine.

regards
Santosh.
e- mail at :  santoshp@xxxxxxxxxxxxxxxxx
FPC-IS, ITS, Tata Steel.
Jamshedpur, India.
Tel : 2147095 (O)



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