There are two statistics log files, named pdstj1 and pdstj2, under the $PDDIR/spool directory. HiRDB creates these statistics log files automatically. The HiRDB administrator must specify the size of the statistics log file in the pd_stj_file_size operand. The following points should be noted about determining this file size:

• The total size of the statistics log information to be collected should be specified as the file size. If multiple sets of statistical information are to be collected concurrently, the value specified in the pd_stj_file_size operand must be greater than the sum of the sizes of those statistics logs. For details about formula for determining the size of a statistics log, see the manual HiRDB Version 9 System Definition.
• Whether the various types of statistics log information are collected depends on the type of server, as shown in the table below. The HiRDB administrator must take this into account in determining the file size.
  

  Table 22-2 Servers subject to collection of statistics log information

  Type of statistics log		HiRDB single server configuration	HiRDB parallel server configuration
  		SDS	MGR	FES	DS	BES
  System activity statistical information	sys	Y	Y	Y	Y	Y
  UAP statistical information	uap	Y	--	Y	--	--
  SQL statistical information	sql	Y	--	Y	--	--
  Global buffer pool statistical information	buf	Y	--	--	Y	Y
  Statistical information on HiRDB files for database manipulation	fil	Y	--	--	Y	Y
  Deferred write processing statistical information	dfw	Y	--	--	Y	Y
  Index statistical information#	idx	Y	--	--	Y	Y
  SQL static optimization information	sop	Y	--	Y	--	--
  SQL dynamic optimization information	dop	Y	--	Y	--	--
  SQL object statistical information	pcd	Y	--	Y	Y	Y
  SQL statement statistical information	sqh	Y	--	Y	--	--
  Statistics on SQL object transfer	obj	--	--	--	Y	Y

Y: Statistics log information that is collected

--: Statistics log information that is not collected

Note

• The CONNECT/DISCONNECT statistical information collected by the pdhibegin operand is output to the system log file, not to the statistics log file; for details, see 22.2 Collecting tuning information from the system log.
• In the case of a utility special unit, only system activity statistical information can be collected.

#: Information on index page splits is not collected as part of the statistics log. For information on how to collect this information, see 22.2 Collecting tuning information from the system log.

When a statistics log file becomes full during output of statistics log information, HiRDB switches outputs of the information to the other statistics log file. This is called statistics log file swapping. When statistics log file swapping occurs, new information is written over any existing statistics log information in the swapped-in file. For this reason, as soon as a statistics log file is swapped out, the HiRDB administrator should unload it and create an unload statistics log file. The following figure shows the procedure for swapping the statistics log files.

Figure 22-1 Swapping of statistics log files