DB2 FOR LUW / DB2FORLUW / 970 - DB2

** This APAR applies only to integrated HA solutions ** 
 
On memory constrained systems or very busy systems ps behavior 
is unpredictable where ps may return the process name in square 
brackets. 
Hence there's a chance that this check: 
 
p_pid=$(ps -u ${DB2INSTANCE?} -o args | grep -v "^db2sysc [0-9]" 
| grep -c "^db2sysc") 
 
returns 0, which in turns makes this script return a status of 2 
i.e. the instance is down.

**************************************************************** 
* USERS AFFECTED:                                              * 
* All users using integrated HA solution                       * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* The ps command in highly stressed environments can return    * 
* wrong                                                        * 
* values which can throw off the script and cause involuntary  * 
*                                                              * 
* cycling of the instance. The fix will provide a fool proof   * 
* way                                                          * 
* of verification of the instance so that the false negatives  * 
* are                                                          * 
* reduced to almost zero.                                      * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Fixed in v97fp3.                                             * 
**************************************************************** 
The ps command in highly stressed environments can return wrong 
values which can throw off the script and cause involuntary 
cycling of the instance. The fix will provide a fool proof way 
of verification of the instance so that the false negatives are 
reduced to almost zero.

To avoid these "false negatives", modify this line to check for 
square bracket and return unknown if it is found. 
 
 
Original: 
  p_pid=$(ps -u ${DB2INSTANCE?} -o args | grep -c "^db2sysc 
${NN?}[ ]*$") 
   if [[ $p_pid == 0 && $NN -eq 0 ]]; then 
      p_pid=$(ps -u ${DB2INSTANCE?} -o args | grep -v "^db2sysc 
[0-9]" | grep -c "^db2sysc") 
   fi 
 
New: 
  p_out=$(ps -u ${DB2INSTANCE?} -o args | egrep "^db2sysc 
${NN?}[ ]*$|^db2sysc[ ]*$|^\[db2sysc\]") 
   p_pid=$(echo $p_out | grep -c "\[db2sysc\]") 
   if [[ $p_pid != 0 ]]; then 
      logger -i -p err -t $0 "ps returns [db2sysc]" 
      echo 0 
      return 0 
   fi 
 
   p_pid=$(echo $p_out | grep -c "db2sysc ${NN?}") 
   if [[ $p_pid == 0 && $NN -eq 0 ]]; then 
      p_pid=$(echo $p_out | grep -c "db2sysc") 
   fi

DB2 Version 9.7 Fix Pack 3 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 3a for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
 

Fixed in v97fp3. 
 
In the script db2V97_monitor.ksh modify the ps command checks 
with the following lines: 
 
# If home dir not accessible, use plain old ps ... 
 
 
  p_out=$(ps -u ${DB2INSTANCE?} -o args | egrep "^db2sysc 
 
 
${NN?}[ ]*$|^db2sysc[ ]*$|^\[db2sysc\]") 
 
 
 
  p_pid=$(echo $p_out | grep -c "db2sysc ${NN?}") 
 
 
  if [[ $p_pid == 0 && $NN -eq 0 ]]; then 
      p_pid=$(echo $p_out | grep -c "db2sysc") 
 
 
  fi 
 
  if [[ $p_pid == 0 ]]; then 
      p_pid=$(echo $p_out | grep -c "\[db2sysc\]") 
 
 
      if [[ $p_pid != 0 ]]; then 
 logger -i -p err -t $0 "ps returns [db2sysc]: returning 
 
 
0" 
 
 
 echo 0 
 return 0 
      fi 
      rc=1 
  else 
      rc=0 
  fi 
 
Pls. ratify it with DB2 support before deploying it in 
production.

In the script db2V97_monitor.ksh modify the ps command checks 
with the following lines: 
       # 
If home dir not accessible, use plain old ps ... 
 
p_out=$(ps -u ${DB2INSTANCE?} -o args | egrep "^db2sysc 
 
${NN?}[ ]*$|^db2sysc[ ]*$|^\[db2sysc\]") 
 
 
 p_pid=$(echo $p_out | grep -c "db2sysc ${NN?}") 
 
  if [[ $p_pid == 0 && $NN -eq 0 ]]; then 
     p_pid=$(echo $p_out | grep -c "db2sysc") 
 
  fi 
 
if [[ $p_pid == 0 ]]; then 
   p_pid=$(echo $p_out | grep -c "\[db2sysc\]") 
 
    if [[ $p_pid != 0 ]]; then 
     logger -i -p err -t $0 "ps returns [db2sysc]: returning 
 
0" 
 
 echo 0 
       return 0 
    fi 
   rc=1 
else 
   rc=0 
fi 
 
Pls. ratify it with DB2 support before deploying it in 
production.

forerunner  : APAR is sysrouted TO one or more of the following: IC69573 
follow-up : 

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

23.06.2010
13.04.2011
13.04.2011

9.7.FP3