This parameter defines the size of each primary and secondary log file. The size of these log files limits the number of log records that can be written to them before they become full and a new log file is required.
The use of primary and secondary log files as well as the action taken when a log file becomes full are dependent on the type of logging that is being performed:
A primary log file can be reused when the changes recorded in it have been committed. If the log file size is small and applications have processed a large number of changes to the database without committing the changes, a primary log file can quickly become full. If all primary log files become full, the database manager will allocate secondary log files to hold the new log records.
When a primary log file is full, the log is archived and a new primary log file is allocated.
Recommendation: You must balance the size of the log files with the number of primary log files:
| Note: | The total log file size limit is 4 GB. That is, the number of log files (logprimary + logsecond) multiplied by the size of each log file in bytes (logfilsiz * 4096) must be less than 4 GB. |
A log file that is too small can affect system performance because of the overhead of archiving old log files, allocating new log files, and waiting for a usable log file.
A log file that is too large can reduce your flexibility when managing archived log files and copies of log files, since some media may not be able to hold an entire log file.
If you are using log retention, the current active log file is closed and truncated when the last application disconnects from a database. When the next connection to the database occurs, the next log file is used. Therefore, if you understand the logging requirements of your concurrent applications you may be able to determine a log file size which will not allocate excessive amounts of wasted space.