CHECKPOINT TYPE field (CHKTYPE subsystem parameter)

The CHKTYPE subsystem parameter indicates whether the interval between log checkpoints is to be based on the number of written log records, the time between checkpoints, or both.

Acceptable values:	CHECKPPOINT TYPE field: LOGRECS, MINUTES, BOTH CHKTYPE subsystem parameter: SINGLE, BOTH
Default:	MINUTES
Update:	option 42 on panel DSNTIPB
DSNZP`xxx`:	DSN6SYSP CHKTYPE

The CHECKPOINT TYPE field and CHKTYPE subsystem parameters use different values.

CHECKPOINT TYPE field value descriptions

The following values can be specified in the CHECKPOINT TYPE field on panel DSNTIPL1. If you run the installation or migration CLIST, the setting of the CHECKPOINT TYPE field determines the setting of the CHKTYPE subsystem parameter. The setting of the CHECKPOINT TYPE field also defines which settings are allowed in the RECORDS/CHECKPOINT and MINUTES/CHECKPOINT fields.

MINUTES: Log checkpoints occur at an interval of a certain number of minutes, as specified by the CHKFREQ subsystem parameter. The CHKFREQ subsystem parameter is set through the MINUTES/CHECKPOINT field, and the CHKLOGR and CHKMINS subsystem parameters are both assigned a value of NOTUSED. When MINUTES is specified in the CHECKPOINT TYPE field, the CHKTYPE subsystem parameter is set to SINGLE.
LOGRECS: Log checkpoints occur after a certain number of log records are created, as specified by the CHKFREQ subsystem parameter. The CHKFREQ subsystem parameter is set through the RECORDS/CHECKPOINT field, and the CHKLOGR and CHKMINS subsystem parameters are both assigned a value of NOTUSED. When LOGRECS is specified in the CHECKPOINT TYPE field, the CHKTYPE subsystem parameter is set to SINGLE.
BOTH: Log checkpoints occur after a specified number of log records are created or after a specified number of minutes, whichever occurs first. The number of log records is specified by the CHKLOGR subsystem parameter and the number of minutes is specified by the CHKMINS subsystem parameter. These subsystem parameters are set through the RECORDS/CHECKPOINT and MINUTES/CHECKPOINT fields, respectively. The CHKFREQ parameter is assigned a value of NOTUSED. When BOTH is specified in the CHECKPOINT TYPE field, the CHKTYPE subsystem parameter is set to BOTH.

CHKTYPE subsystem parameter value descriptions

The following settings are valid for the CHKTYPE subsystem parameter:

SINGLE

The CHECKPOINT TYPE panel field setting is LOGRECS or MINUTES. The CHKFREQ subsystem parameter setting determines the checkpoint frequency, depending on the value specified:

1–5: The number of minutes between checkpoints.
1000–16 000 000: The number of log records between checkpoints. CHKFREQ settings from 200–999 are automatically increased to 1000.

The CHKLOGR and CHKMINS subsystem parameters must both be set to NOTUSED.

BOTH

Log checkpoints occur after a specified number of log records are created or after a specified number of minutes, whichever occurs first. The CHKLOGR subsystem parameter specifies the number of log records and the CHKMINS subsystem parameter specifies the number of minutes. The CHKFREQ subsystem parameter must be set to NOTUSED.

Panel fields and subsystem parameter settings for Db2 checkpoint frequency

The following table summarizes how the CHECKPOINT TYPE, MINUTES/CHECKPOINT, and RECORDS/CHECKPOINT fields on panel DSNTIPL1 set the related subsystem parameters to specify the Db2 checkpoint frequency. The following table shows panel DSNTIPL1 fields and related subsystem parameters for controlling the Db2 checkpoint frequency.

CHECKPOINT TYPE field	CHKTYPE subsystem parameter	CHKFREQ subsystem parameter	CHKMINS subsystem parameter	CHKLOGR subsystem parameter
MINUTES (default)	SINGLE	1–5 (default 3) Set in the MINUTES/CHECKPOINT field to specify the number of minutes between checkpoints.	NOT USED	NOT USED
LOGRECS	SINGLE	1000–16 000 000 Set in the RECORDS/CHECKPOINT field to specify the number of log records between checkpoints.	NOT USED	NOT USED
BOTH	BOTH	NOT USED	1–5 Set in the MINUTES/CHECKPOINT field to specify the number of minutes between checkpoints.	1000–99 999 999 Set in the RECORDS/CHECKPOINT field to specify the number of log records between checkpoints.