Choosing a checkpoint frequency
If log data sets are too small, checkpoints occur too frequently, and database writes are not efficient.
About this task
At least one checkpoint is taken each time that Db2 switches to a new active log data set. The recommendation is to provide enough active log space for at least 10 checkpoint intervals.
Procedure
To improve the log data set size:
Set the checkpoint frequency interval to be greater than 1 minute during peak periods
In most cases, the recommendation is to specify a checkpoint interval of 2 to 5 minutes.
You can also specify the interval in terms of the number of log records that are written between checkpoints or the number of minutes between checkpoints. The follow table summarizes how the DSNTIPL1 panel fields and related subsystem parameters specify the Db2 checkpoint interval.
| CHECKPOINT TYPE field | CHKTYPE subsystem parameter | CHKFREQ subsystem parameter | CHKMINS subsystem parameter | CHKLOGR subsystem parameter |
|---|---|---|---|---|
| MINUTES (default) | SINGLE |
|
NOT USED | NOT USED |
| LOGRECS | SINGLE |
|
NOT USED | NOT USED |
| BOTH | BOTH | NOT USED |
|
|