The following figure shows the memory allocation for each unit of a HiRDB parallel server configuration.

Figure 15-2 Memory allocation for each unit of a HiRDB parallel server configuration

The following table lists details about the shared memory for each unit of a HiRDB parallel server configuration.

Table 15-6 HiRDB parallel server configuration shared memory details per unit

Item	Type of shared memory
	Unit controller shared memory	Global buffer shared memory	Utility shared memory	Security audit information buffer shared memory	Inter-process memory communication shared memory	Troubleshooting information acquisition shared memory
Purpose	System control	Global buffers	Communication between the unit controller and utilities	Security audit information buffer	Client-server inter-process communication	Acquisition of troubleshooting information
Processes	All HiRDB processes	Back-end servers, dictionary servers	Utility processes	Front-end servers	Front-end servers, client processes	All HiRDB processes
Number of segments	1	If the facility for dynamic updating of global buffers is not used: 1 to 512#1 If the facility for dynamic updating of global buffers is used: 32-bit mode: 1 to 1,012#1 64-bit mode: 1 to 1,512#1	1	1	Number of clients connected using the PDIPC=MEMORY environment variable (0-2,000) 2	1
Maximum value per segment	See Table 15-7 Size of memory required for each unit of a HiRDB parallel server configuration. Value of the shmmax OS parameter must be equal to or greater than the calculation value.	Divide the segment by the SHMMAX operand value. Value of the shmmax OS parameter must be equal to or greater than the SHMMAX operand value.	See Table 15-7 Size of memory required for each unit of a HiRDB parallel server configuration. Value of the shmmax OS parameter must be equal to or greater than the calculation value.	See Table 15-7 Size of memory required for each unit of a HiRDB parallel server configuration. Value of the shmmax OS parameter must be equal to or greater than the calculation value.	See Table 15-7 Size of memory required for each unit of a HiRDB parallel server configuration. Value of the shmmax OS parameter must be equal to or greater than the calculation value.	10 MB
Allocation conditions	None	There must be a global buffer definition	Specify pd_utl_exec_mode=1	Specify the pd_aud_file_name operand as the HiRDB file system area name for the audit trail.	There are clients connected using the PDIPC=MEMORY environment variable	None
Creation timing	At unit activation (including standby unit activation when user server hot standby or the rapid system switchover facility is used)	At server activation (including standby unit activation when the rapid system switchover facility is used) When pdbufmod -k {add|upd} is executed	When utilities are executed	When a front-end server starts up	When client and server are connected	At unit activation (including standby unit activation when user server hot standby or the rapid system switchover facility is used)
Deletion timing	At next unit activation (including standby unit activation when user server hot standby or the rapid system switchover facility is used)	When pdbufmod -k del is executed For normal termination or planned termination: When the server is terminated For forced termination, abnormal termination, or termination of standby unit when the rapid system switchover facility is used: When the unit is next activated	10 minutes after the utility terminates	When a front-end server quits	When client and server are disconnected	At unit termination
Indication by pdls -d mem	Indicated	Indicated	Indicated	Indicated	Not indicated	Not indicated
SHM-OWNER of pdls -d mem	MANAGER	Server name	UTILITY	AUDDEF	Not indicated	Not indicated
Related operands	pd_shmpool_attribute pd_dic_shmpool_size pd_bes_shmpool_size	pd_dbbuff_attribute pd_dbbuff_modify pdbuffer SHMMAX	pd_utl_exec_mode	Operands related to the security audit facility#2	PDIPC PDSENDMEMSIZE PDRECVMEMSIZE	None
Remarks	--	--	Can be created only when pd_utl_exec_mode=1 (when pd_utl_exec_mode=0, the relevant space is allocated in the unit controller shared memory).	--	--	--

Legend:

--: Not applicable.

#1: Number of global buffers allocated per back-end server or dictionary server.

#2: For details, see the manual HiRDB Version 9 System Definition.