LOGSIZE and LOGFILES and their effect on checkpoints

The LOGSIZE and LOGFILES configuration parameters indirectly affect checkpoints because they specify the size and number of logical-log files. A checkpoint can occur when the database server detects that the next logical-log file to become current contains the most-recent checkpoint record.

If you need to free the logical-log file that contains the last checkpoint, the database server must write a new checkpoint record to the current logical-log file. If the frequency with which logical-log files are backed up and freed increases, the frequency at which checkpoints occur increases. Although checkpoints block user processing, they no longer last as long. Because other factors (such as the physical-log size) also determine the checkpoint frequency, this effect might not be significant.

When the dynamic log allocation feature is enabled, the size of the logical log does not affect the thresholds for long transactions as much as it did in previous versions of the database server. For details, see LTXHWM and LTXEHWM and their effect on logging.

The LOGSIZE, LOGFILES, and LOGBUFF configuration parameters also affect logging I/O activity and logical backups. For more information, see Configuration parameters that affect logging.


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