Operands related to maximum concurrent executions

4) pd_max_users = maximum number of concurrent connections

<unsigned integer>((1-2000))<<10>>

This operand specifies the maximum number of concurrent connections allowed for the HiRDB server. For a HiRDB/Parallel Server, this operand specifies the maximum number of concurrent connections allowed for a single front-end server. If the number of connection requests exceeds the value specified by this operand, HiRDB rejects any additional connection requests (connection requests result in errors). Note that connection in this case means an attempt to connect to a HiRDB server based on a CONNECT statement.

Specification guidelines

When OpenTP1 is used, the connection count is the number of OpenTP1 server processes to be connected to the HiRDB server (including XA connections).
When DBPARTNER/Server is used, the connection count is the number of DBPARTNER/Server connection clients.
When HiRDB SQL Executer is used, the connection count is the number of HiRDB SQL Executer connection clients.
If the multi-connection facility is used, the connection count is the total number of concurrent connections by individual UAPs.
Some of the HiRDB commands and utilities are internally connected to the HiRDB server. Therefore, while these commands and utilities are being executed, the number of users that can be connected temporarily decreases. Determine the operand value by taking this fact into consideration. For details about command and utility connection count, see Maximum number of concurrent executions for commands in the manual HiRDB Version 8 Command Reference.

Notes

If you increase the value of the pd_max_users operand, you must also increase the value of the pd_max_server_process operand. Along with these increases, both the size of the shared memory and the number of ports used by the HiRDB system also increase. For notes related to an increase in the value of the pd_max_users operand (when the number of users is increased), see the HiRDB Version 8 System Operation Guide. If you omit the pd_max_server_process operand, HiRDB automatically computes a value for this operand.
For a multiple front-end server, the maximum number of connection requests that can be processed is obtained by multiplying the value of the pd_max_users operand by the number of front-end servers. However, make sure that the value obtained does not exceed the specifiable upper limit for the pd_max_users operand (2000).

5) pd_max_server_process = maximum-number-of-concurrently-activated-server-processes

<unsigned integer>((50-10000))

Specifies the maximum number of processes that can be activated at the same time in the same unit. The number of server processes includes the number of processes for the system server, individual servers, utilities, etc. (the system server is a server that is used internally by HiRDB).

Specification guidelines

Normally, omit this operand. When it is omitted, the value obtained from the following formula is assumed. HiRDB automatically re-computes the value of this operand if you change any of the operands mentioned in the explanation of a variable.
Default value = a + b (c + 26) + 73 + i + j + k + n
If you choose to specify this operand, use the following formula as a reference for determining the operand value. For a HiRDB/Parallel Server, determine values for all units, and use the largest of these values as a guideline.

Recommended value = a + b [Figure]

(c + d

e + f) + d [Figure]

g + h + i + j + k + n

Variable	Explanation of variable
a	For HiRDB/Single Server: Value of pd_max_users For HiRDB/Parallel Server: Total the values obtained using the following formulas for individual servers inside the unit: Back-end server: Value of pd_max_bes_process Dictionary server: Value of pd_max_dic_process Front-end server: Value of pd_max_users If the pd_max_bes_process or pd_max_dic_process operand is omitted, use the value of the pd_max_users operand. If a unit contains multiple back-end servers, compute a value for each back-end server. For a unit to which the standby-less system switchover (effects distributed) facility is to be applied, substitute the value of the pd_ha_max_server_process operand.
b	For HiRDB/Single Server: 1 For HiRDB/Parallel Server: Server count inside the unit (server count allocated to the unit by the pdstart operand of the system common definition) For a unit to which the standby-less system switchover (effects distributed) facility is to be applied, substitute the value of the pd_ha_max_act_guest_servers operand.
c	Concurrently executable process count in full recovery processing (value of the pd_max_recover_process operand)
d	Maximum number of concurrently executable utilities ("2" is the default value for this operand)
e	Number of processes to be started in each server by the utility (set this variable to 10)
f	Number of processes to be started by HiRDB for controlling the server (set this variable to 6)
g	Number of processes to be started in each unit by the utility (set this variable to 10)
h	Number of processes to be started by HiRDB for controlling the unit (set this variable to 50)
i	For HiRDB/Single Server: 1 For HiRDB/Parallel Server: Number of back-end servers inside the unit For a unit to which the standby-less system switchover (effects distributed) facility is to be applied, substitute the value of the pd_ha_max_act_guest_servers operand.
j	For HiRDB/Single Server: value of the pd_max_ard_process operand For HiRDB/Parallel Server: number-of-back-end-servers-inside-the-unit value specified for the pd_max_ard_process operand + number-of-dictionary-servers-inside-the-unit value specified for the pd_max_ard_process operand For a unit to which the standby-less system switchover (effects distributed) facility is to be applied, add the following value: maximum-value-of-pd_max_ard_process-operand-for-guest-BES value of the pd_ha_max_act_guest_servers operand
k	Depends on the value specified for the pd_process_terminator operand. resident: 1 fixed (default value): pd_process_terminator_max operand value nonresident: 0
n	For HiRDB/Single Server: pd_dfw_awt_process operand value For HiRDB/Parallel Server: number-of-back-end-servers pd_dfw_awt_process operand value + number-of-dictionary-servers pd_dfw_awt_process operand value For a unit to which the standby-less system switchover (effects distributed) facility is to be applied, add the following value: maximum-value-of-pd_dfw_awt_process-operand-value-for-guest-BES pd_ha_max_act_guest_servers operand value

Relationship to other operands

This operand's value limits the maximum value of the pd_process_count operand.
If you need to adjust the value for each unit because the server configuration in each unit is different, specify the pd_max_server_process operand in the unit control information definition.

Notes

This specification value includes the number of processes for servers and utilities in the unit. If this value is too small, the following may occur:
Unit or server startup process results in an error
Transaction recovery cannot be performed
HiRDB planned termination cannot be performed
Because the number of processes that can actually be activated depends on factors such as the system resources, it may be necessary to adjust the resources or to change the locations of servers in some cases.

6) pd_max_access_tables = concurrently-accessible-base-tables-count

<unsigned integer>((4-32000))<<64>>

Specifies the maximum number of tables that can be accessed concurrently in a single transaction. The number of tables that can be accessed concurrently means the total number of tables coded in the SQL statements in a transaction. If the number specified by this operand is exceeded, an error results, processing returns to the UAP, and rollback processing is executed.

Specification guidelines

If the same table is specified in different SQLs, the total number of times the table is used must be counted.
If the same table is specified more than once in the same SQL, the total number of times the table is used must be counted.
To set up referencing privileges for dictionary tables, the value obtained by multiplying the number of dictionary tables to be accessed by 5 must be added to the concurrently accessible base tables count (for details about the dictionary table referencing privilege, see the HiRDB Version 8 System Operation Guide).

7) pd_utl_exec_mode = 0 | 1

Specifies a value that indicates the maximum number of concurrent executions of utilities, as indicated below:

Utility	Maximum number of concurrent executions
Utility	pd_utl_exec_mode = 0	pd_utl_exec_mode = 1
Database load utility	32	pd_max_users value
Database reorganization utility	32
Database copy utility^*	32
Database recovery utility	32
Database condition analysis utility	16
Optimization information collection utility	16	pd_max_users value 2

^* The number of backup files affects the maximum number of concurrent executions of the database copy utility. As the number of backup files increases, the maximum number of concurrent executions decreases. For details, see the explanation of the database copy utility in the HiRDB Version 8 Command Reference.

Specification guidelines

Specifying 0 fixes the size of the HiRDB shared memory to be used by utilities.
When 1 is specified, the shared memory needed for utility execution is allocated dynamically during utility execution.
When the value of pd_max_users is 32 or less and the number of concurrent executions of utilities is less than the value specified in pd_max_users, specifying pd_utl_exec_mode = 1 will reduce the amount of shared memory that is used.
If a HiRDB/Parallel Server satisfies the following condition, specify 1 for this operand.
total-number-of-BESs 2 number-of-utilities-to-be-concurrently-executed 824

Note

If the number of back-end servers is large, a shared memory shortage may prevent utility execution.

8) pd_max_commit_write_reclaim_no = maximum-number-of-concurrent-executions-of-pdreclaim-commands-with-p-option-specified

<unsigned integer>((0-2000)) <<10>>

Specifies the maximum number of pdreclaim commands with the -p option specified that can be executed concurrently. For a HiRDB/Parallel Server, this operand specifies the maximum number of concurrent executions per server.

Specifying 0 results in termination with an error of any pdreclaim command in which the -p option is specified. When the number of concurrent executions of pdreclaim commands in which the -p option is specified exceeds the value of this operand, the excess pdreclaim commands in which the -p option is specified terminate with an error.

Specification guidelines: If you specify the -p option in pdreclaim commands, specify the number of concurrent executions per server that executes those commands. If you always omit the -p option from the pdreclaim command, specify 0 (to reduce the size of shared memory used).

Notes: If you specify a large value for this operand, check and, if necessary, revise the memory requirement, because the shared memory used by the back-end server, dictionary server, and single server increases. For details about estimating the shared memory, see the HiRDB Version 8 Installation and Design Guide.

Relationship to other operands: If v6compatible or v7compatible is specified in the pd_sysdef_default_option operand, 0 is assumed when this operand is omitted. This means that if you specify v6compatible or v7compatible in the pd_sysdef_default_option operand and omit this operand, pdreclaim commands in which the -p option is specified cannot be executed.

2.3.2 Operands related to maximum concurrent executions