Operands related to lock

19) pd_lck_wait_timeout = lock-release-wait-time: <unsigned integer>((0-65535)) (seconds); Specifies in seconds the maximum amount of time to wait for lock release (the maximum amount of time in lock release wait status).This is the elapsed time from when a lock release request is placed in wait status until it is released.; If the wait status is not released within the specified amount of time, the SQL will return an error. When 0 is specified, lock wait time will not be monitored and waiting will continue until the wait status is released.

20) pd_lck_release_detect = interval | pipe

Specifies the method to be used by HiRDB to detect lock release (method of detecting whether or not the process that locked a resource has released that lock).

interval:: Determine the lock release status by checking the lock management area at a regular interval.

pipe:: Use a pipe file (process-to-process communication pipe) to receive the lock release notice.

Specification guidelines

Following are guidelines for specifying this operand:

Specified value	HiRDB processing	Advantages and application criteria
interval	Determines whether the lock has been released by checking the lock management area in the shared memory. HiRDB checks the lock management area at a regular interval; this interval is specified by the pd_lck_release_detect_interval operand.	Even if the process that has locked a resource releases the lock, the release will not be detected until the next time the lock management area is checked. Consequently, a UAP that has a fast processing time per transaction may end up waiting for a long time. However, this wait does not place any load on the CPU or open any file. If a small value is specified for the pd_lck_release_detect_interval operand, the CPU usage may increase too much, adversely affecting the throughput. Specifying interval has the effect of reducing the CPU load when a slow CPU is being used.
pipe	Uses a pipe file to determine whether or not the lock has been released. The process that has locked a resource sends a lock release notice to the process that is waiting for release. When the process that has locked the resource releases it, the process that is waiting for the release can detect the release. Because a maximum of one file descriptor is used per process, it is necessary to re-estimate the number of file descriptors.	Throughput improves if the processing time per transaction does not exceed the value specified by the pd_lck_release_detect_interval operand. CPU workload increases if lock release wait occurs frequently. Additionally, the number of open files is increased because pipe files are opened. Specify pipe when there are system resources (CPU and file descriptors) that can be spared.

Notes

When pipe is specified for the first time after HiRDB has been newly installed, the pipe file is initialized during activation of the unit. Consequently, unit activation completion may take longer than expected.
When pipe has been specified, the pipe file is opened when lock-release wait occurs. Therefore, add to the estimate for the file descriptors for the entire system (nfile in the case of HP-UX) the value determined from the following formula (as applicable):
HiRDB/Single Server:
pd_max_users operand value + pd_max_reflect_process_count value
HiRDB/Parallel Server:
(a + 3 server-count-inside-unit) b
a: Total of the values determined for all of the servers inside the unit, computed using the following formulas:
Back-end server: Value of pd_max_bes_process + pd_max_reflect_process_count
Dictionary server: Value of pd_max_dic_process + pd_max_reflect_process_count
If the pd_max_bes_process or pd_max_dic_process operand is omitted, use the value of pd_max_users. If a unit contains multiple back-end servers, compute a value for each back-end server.
b: 16 (number of threads waiting for lock release)
When pipe is specified in the Linux version, the pipe file is opened when lock-release wait occurs. In this case, it is necessary to specify the maximum number of open files in the system, including open pipe files, using the method described below.
Specify the following in /etc/rc.d/rc.local:
/sbin/sysctl -w fs.file-max = maximum-number-of-open-files-in-system

21) pd_lck_release_detect_interval = lock-release-detection-interval

<unsigned integer>((1-1000)) (Milliseconds)

Specifies the interval at which the lock management area is to be checked.

When 49 or less is specified
The interval will begin at the value specified by this operand and thereafter will be 50 milliseconds.
When 50 or more is specified
The interval will begin at 50 milliseconds and thereafter will be the value specified by this operand.

Condition: The interval option must be specified for the pd_lck_release_detect operand.

Specification guidelines

As a rule, this operand can be omitted. This operand should be specified (instead of using the default value) only when there is a performance problem.
If too small a value is specified, the CPU workload will increase if lock release waits occur frequently.
If too large a value is specified, the wait time may increase.
The value to be specified can be determined by referring to WAIT TIME in the statistical information related to system operation from the statistics analysis utility. If the wait time that is output in the statistical information is smaller than the value of this operand, the value of this operand should be reduced.

22) pd_lck_deadlock_info = Y | N: Specifies whether or not deadlock information and timeout information are to be output. These types of information are output to a directory named $PDDIR/spool/pdlckinf. For details about the deadlock and timeout information, see the HiRDB Version 8 System Operation Guide.; Y: Output deadlock information and timeout information.; N: Do not output deadlock information or timeout information.

3.3.9 Operands related to lock