This section explains the procedure for tuning the specifications in the following operands that determine the maximum number of active processes:

• pd_max_users
• pd_max_bes_process
• pd_max_dic_process

Information to be referenced

Reference the following statistical information related to system operations:

• Number of service requests exceeding the maximum number of active processes (#OF REQ PROCESS OVER MAX)
• Number of service processes under service execution (#OF PROCESS ON SERVICE)

Purpose

• To utilize memory resources efficiently by combining the number of active server processes that were actually executing services during processing with the maximum number of active processes specified by these operands.
• To prevent service from being denied by increasing the maximum number of active processes (when it turns out that the estimated value is too small).

Evaluating the analysis results

When the operand value is greater than the number of server processes engaged in service execution

It is likely that the operand value can be reduced.

Reduce each server's maximum number of active processes to a value close to the maximum value for the number of server processes during service execution (#OF PROCESS ON SERVICE). The following should be noted in such a case:

• Depending on other servers' status, the value should not be reduced to the maximum value for the number of server processes during service execution (#OF PROCESS ON SERVICE). For example, this is true when service requests from multiple front-end servers might concentrate in a specific back-end server or when a particular front-end server in the unit is handling too much processing.
• In tuning pd_max_bes_process or pd_max_dic_process, if the specified value is smaller than the value of pd_max_users, the value of pd_max_users is assumed.

When there are service requests exceeding the maximum number of active processes

The operand value should be increased.

In this case, the operand value should be increased such that no service request is denied. The following should be noted for each server with respect to the tuning procedure:

• For the front-end server or single server, if a service request received by the server exceeds the maximum number of active processes, the client retries up to the following number of times:
  HiRDB client with HiRDB Version 4.0 03-03 or earlier: 100 times
  HiRDB client with HiRDB Version 4.0 04-00 or later: 10 times
  The number of service requests exceeding the maximum number of active processes (#OF REQ PROCESS OVER MAX) includes the retries count; this must be taken into account when this parameter is tuned.
  
• For a back-end server or dictionary server, a service request is not retried; therefore, the number of service requests exceeding the maximum number of active processes (#OF REQ PROCESS OVER MAX) can be used for tuning.

If the value of pd_max_users is increased and the resulting value exceeds the value of pd_max_bes_process or pd_max_dic_process, the value of pd_max_bes_process or pd_max_dic_process is also assumed to increase up to the value of pd_max_users.

Actions to be taken

• For the front-end server or single server, modify the value of pd_max_users.
• For a back-end server, modify the value of pd_max_bes_process.
• For a dictionary server, modify the value of pd_max_dic_process.