10.12.1 System log file configuration and server definition specification
System log files consist of two types of files: a master log file and a set of user log files. In the master log file, history information (event logs) regarding system control (such as start and end of transactions) and management information of user log files are output. When the HADB server starts, only one master log file is automatically created.
In user log files, operation history information (user logs) of a database is output. One user log file is created for each transaction that updates the database or each real thread. When the HADB server starts, user log files are automatically created. The number and initial size of user log files to be created are determined by the definitions in the server definition.
- Server definition operands related to user log files
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adb_log_usrfile_num
This operand specifies the number of user log files that are created when the HADB server starts.
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adb_log_usrfile_size
This operand specifies the initial size of user log files and the trigger for reducing the size of user log files.
If the size of a user log file exceeds the initial size specified here for user log files, the user log file is expanded automatically. Note that, however, expansion of user log files will have a significant impact on update processing performance. For details, see 13.1.8 Expanding the initial size of user log files.
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adb_log_usrbuf_num
This operand specifies the number of user log buffer files.
For details about each operand, see 7.2.3 Operands related to system logs (set format).
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- Note
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For details about system log files, see (2) System log in 2.11.1 Recovery flow based on a restart.
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For details about how to determine the number of user log files, see 6.12.15 Determining the number of user log files.
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