B.4 Embedded database processes

(1) Process configuration

The following figure shows the configuration of the embedded database processes generated when the embedded database is used as the scheduler database of JP1/AJS3 - Manager in UNIX. This figure is useful for monitoring processes because it shows the parent-child relationship of the processes of the entire embedded database.

Figure B‒5: Configuration of embedded database processes in UNIX

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(2) Processes in Windows

The following explains the embedded database processes in Windows.

The Windows version of the embedded database consists of the following two types of processes:

• Parent process

  A parent process consists of at least one child process.

• Child process

The status of parent and child processes can be checked on the Processes page in the Task Manager window.

The following table lists the parent and child processes. In the table, the number in parentheses following a process name indicates the number of instances that are activated concurrently.

Table B‒13: List of parent and child processes for the Windows version of the embedded database

Parent process (instances)	Explanation	Child process (instances)	Explanation
pdservice.exe (1)	JP1/AJS3 Database service process	pdprcd.exe (1)	Windows service control
pdprcd.exe (1)	Process server process, which manages the processes related to the embedded database	pdrsvre.exe (3)#1	Cleanup process, which performs cleanup processing after an embedded database process has terminated abnormally
		pdmlgd.exe (1)	Message log server process, which controls message output
		pdrdmd.exe (1)	System manager process, which controls the starting and stopping of units and manages users who want to connect
		pdstsd.exe (1)	Status server process, which controls input and output for the status file for units
		pdscdd.exe (1)	Scheduler process, which assigns a transaction to the single server process
		pdtrnd.exe (1)	Transaction server process, which controls transactions
		pdtrnrvd.exe (1 to 128)#2, #3	Transaction restoration process, which controls committing and restoration of transactions
		pdlogd.exe (1)	Log server process, which controls the acquisition of system log data and log-related processes
		pd_buf_dfw.exe (1)	Deferred write process, which controls background writing to the database storage disk
		pdlogswd.exe (1)	Log swapper process, which allocates and de-allocates files related to the system log, manages input and output, and acquires synchronization point dumps
		pdsds.exe (16 to 128)#3, #4	Single server process, which processes the SQL
pdsha.exe (1)#5	JP1/AJS3 Database ClusterService service process	--	Embedded database service for clusters

#1

When the version of the embedded database is 07-03 or earlier, two instances of this process are activated.

#2

Initially, only one instance is activated. Thereafter, each time a pdsds.exe process terminates abnormally, the number of instances temporarily increases.

#3

If the value of the pd_max_users operand in the system common definition file (pdsys) is changed, the new value becomes the maximum number of instances that can be activated.

#4

Initially, 16 instances are activated. Thereafter, the number of activated instances can increase to a maximum of 128 in response to the number of access requests for the embedded database.

#5

This process is activated if the version of the embedded database is earlier than 10-00.

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(3) Processes in UNIX

The following explains the embedded database processes in UNIX.

The UNIX version of the embedded database consists of the following two types of processes:

• Parent process

  A parent process consists of at least one child process.

• Child process

The status of parent and child processes can be checked by using the ps command.

The following table lists the parent and child processes. In the table, the number in parentheses following a process name indicates the number of instances that are activated concurrently.

Table B‒14: List of parent and child processes for the UNIX version of the embedded database

Parent process (instances)	Explanation	Child process (instances)	Explanation
pdmgrd (1)	Process server management process	pdprcd (1)	This process manages starting and stopping of the process server process.
pdprcd (1)	Process server process, which manages the processes related to the embedded database	pdrsvre (3)#1	Cleanup process, which performs cleanup processing after an embedded database process has terminated abnormally
		pdmlgd (1)	Message log server process, which controls message output
		pdrdmd (1)	System manager process, which controls the starting and stopping of units and manages users who want to connect
		pdstsd (1)	Status server process, which controls input and output for the status file for units
		pdscdd (1)	Scheduler process, which assigns a transaction to the single server process
		pdtrnd (1)	Transaction server process, which controls transactions
		pdtrnrvd (1 to 128)#2, #3	Transaction restoration process, which controls the committing and restoration of transactions
		pdlogd (1)	Log server process, which controls the acquisition of system log data and log-related processes
		pd_buf_dfw (1)	Deferred write process, which controls background writing to the database storage disk
		pdlogswd (1)	Log swapper process, which allocates and deallocates files related to the system log, manages input and output, and acquires synchronization point dumps
		pdsds (16 to 128)#3, #4	Single server process, which processes the SQL

#1

When the version of the embedded database is 07-03 or earlier, two instances of this process are activated.

#2

Initially, only one instance is activated. Thereafter, each time a pdsds process terminates abnormally, the number of instances temporarily increases.

#3

If the value of the pd_max_users operand in the system common definition file (pdsys) is changed, the new value becomes the maximum number of instances that can be activated.

#4

Initially, 16 instances are activated. The number of activated instances can increase to a maximum of 128 in response to the number of access requests for the embedded database.

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