(a) exectime=pdreclaim-monitoring-time
~<unsigned integer> ((0-35791394))
Specifies the pdreclaim execution monitoring time in minutes.
- Guideline for the specification value
- The purpose of this operand is to detect a no-response error, not to monitor the execution time of a long transaction. Therefore, you should specify a sufficient time for processing the applicable table. For example, to monitor the execution time of a pdreclaim command that should terminate in 7 to 8 minutes, specify exectime=20, not exectime=10.
- Rules
- If you specify 0 in this operand, the utility's execution time will not be monitored.
- If this operand is omitted, a value is selected from the system definition in the order listed below and that value takes effect:
1. pd_utl_exec_time
2. pd_cmd_exec_time
- If processing does not terminate within the specified amount of time, the system terminates pdreclaim forcibly and acquires error information in order to determine the cause of the no-response. Note that the targets of this monitoring are the utility server processes for pdrorg (0mrorg) and the single server (or back-end server). In the event of an error in the command process (pdreclaim or pdrorg), pdreclaim cannot be terminated forcibly. For details about the error information that is collected, see the pd_utl_exec_time operand in the manual HiRDB Version 9 System Definition.
(b) globalbuffer_lru={yes|no}
Specifies whether pages read by pdreclaim are to be subject to LRU management. The default value depends on the mode, as shown below:
Default operation mode | Default value |
---|
Recommended mode | no |
Compatibility mode | yes |
If this operand's value is no, LRU management is not applied to the global buffer used by pdreclaim, in which case pages read by pdreclaim are always treated as the oldest page. As a result, pages read by pdreclaim will be removed first in the event of a shortage of space in the global buffer, thereby protecting the application's performance. If this operand's value is yes, LRU management is applied to the global buffer used by pdreclaim. In this case, pages read by the application will be removed first in the event of a shortage of space in the global buffer, resulting in degradation of the application's performance. Specify yes if the execution speed for pdreclaim is more important than the performance of the application that is executed concurrently with or subsequent to pdreclaim.
- Guidelines for the specification value
- Any time you execute this utility concurrently with an application, specify no to achieve stable application performance.
- Even if you do not execute this utility concurrently with an application, specify no in the following cases:
Segments are to be released with -j specified.
Used free pages are to be released from a table and the value of the pd_dbreuse_remaining_entries operand in the system common definition is ALL in the system common definition.
All data is read into the buffer.
Specify yes if you want to reduce the execution time of pdreclaim under the following conditions:#
Used free pages are to be released from a table and the value of the pd_dbreuse_remaining_entries operand in the system common definition is NONE.
Used free pages are to be released from indexes.
#
After pdreclaim has terminated, pages in the global buffer that were used previously by the application are replaced. Therefore, the application's buffer hit rate might decrease and delays might occur, which could affect the application's performance.