When you use the performance trace facility, note the following points:

• The performance trace facility does not apply locking since concurrent execution of processes is given higher priority. As a result, some trace information might not be output or, in some cases, invalid information might be output.
  When you reference performance trace information, collect the information multiple times and verify that normal trace information has been collected (performance trace sequence numbers are output in the correct sequence).
  
• Performance trace information is collected by the troubleshooting information collection process (pdprfd process). If the pdprfd process terminates abnormally while HiRDB is active, the KFPS05901-W message is output and the pdprfd process ends, but HiRDB continues to run. In this case, performance trace information is not collected. To resume collection of performance trace information, terminate HiRDB and then restart it. This will reactivate the pdprfd process.
• You can use one of the following methods to check whether the pdprfd process is running:
  Use the OS's ps command or a similar tool to check the status of the pdprfd process.
  Execute the pdprflevel command and make sure no error occurs.
  Note that you cannot use the pdls -d prc command to check the operating status of the pdprfd process.
  
• If you plan to reference performance trace information among multiple machines, we recommend that you first synchronize the time among the machines. If the time is not synchronized, you must use Excel or another such tool to correct the time.
• Performance trace information is output to the performance trace information file in binary format. Therefore, if you use a transfer mode such as ftp to transfer the file, choose one that supports binary format.
• Do not store anything other than performance trace information files in the performance trace information file output directory. For example, if you perform file compression under the performance trace information file directory, the OS command might create a temporary file. To avoid such an event, copy the performance trace information file to a work directory before referencing or editing it.