DB2 FOR LUW / DB2FORLUW / 970 - DB2

This issue was introduced by the fix for APAR IC93275 and only 
affects version 9.7 Fix Pack 9 and 9a. 
 
The problem can occur for a SQL statement that contains an ORDER 
BY and FETCH FIRST N ROWS clause, where N > 1, and the optimizer 
produces a query execution plan containing a truncated SORT 
operation with an input estimated cardinality of exactly 0. 
This problem is most likely to occur if statistics are collected 
on an empty table and not updated after more than one row is 
inserted into the table. 
 
You can identify the problem by collecting an EXPLAIN of the 
query and identifying there is a SORT operator with an input 
cardinality of 0 such as: 
 
   0 
TBSCAN 
(   2) 
... 
  | 
   0 
SORT 
(   3) 
... 
  | 
   0 
NLJOIN 
(   4) 
... 
 
and the operator details shows it is truncated, with NUMROWS set 
to 1: 
 
    3) SORT  : (Sort) 
 
... 
 
        Arguments: 
        --------- 
... 
        NUMROWS : (Estimated number of rows) 
            1 
... 
        TRUNCSRT: (Truncated sort (for Fetch First n Rows Only)) 
            TRUE

**************************************************************** 
* USERS AFFECTED:                                              * 
* only version 9.7 fix pack 9 is impacted                      * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* upgrade to version 9.7 fix pack 10                           * 
****************************************************************

If your affected statement references a table with a cardinality 
statistic of 0, collect updated statistics on the table.

First fixed in version 9.7 fix pack 10

not known / see Local fix

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

08.01.2014
10.11.2014
10.11.2014

9.7.FP10