ttCkptConfig
ttCkptConfig
become effective immediately. Thus, changes to ckptRate
can take effect on a checkpoint that is currently in progress.
Changes made to the background checkpointer using ttCkptConfig
are
persistent. Subsequent loads of the database retain the new settings, unless the
CkptFrequency and CkptLogVolume connection attributes are specified in the DSN or connection
string, in which case the attribute values are used instead.
Required Privilege
This procedure requires no privilege to query the current values. It requires the ADMIN
privilege to change the current values.
Usage in TimesTen Scaleout and TimesTen Classic
This procedure is supported in TimesTen Classic.
TimesTen Scaleout applications can call this built-in procedure.
In TimesTen Scaleout, this procedure returns a row for the element from which it was called.
Syntax
ttCkptConfig(ckptFrequency, ckptLogVolume, ckptRate)
Parameters
ttCkptConfig
has these parameters:
Parameter | Type | Description |
---|---|---|
|
|
Checkpoint frequency in seconds. Values from |
|
|
Log volume between checkpoints in megabytes. Values from |
|
|
Specifies the rate in MB per second at which a checkpoint should be written to disk. A value of |
Result Set
ttCkptConfig
returns the following results.
Column | Type | Description |
---|---|---|
|
|
Currently active setting for checkpoint frequency in seconds. |
|
|
Currently active setting for log volume between checkpoints in MB. |
|
|
Current rate at which TimesTen writes checkpoints to disk. |
Examples
To view the current settings of the background checkpointer configuration parameters, use:
CALL ttCkptConfig; < 600, 32, 0 > 1 row found.
To stop the background checkpointer from initiating checkpoints unless the log reaches its limit, use:
CALL ttCkptConfig(0); < 0, 32, 0 > 1 row found.
To stop the background checkpointer from initiating checkpoints, use:
CALL ttCkptConfig(0, 0); < 0, 0, 0 > 1 row found.
To set the background checkpointer configuration to initiate a checkpoint every 600 seconds or to checkpoint when the log reaches 32 MB (whichever comes first), use:
CALL ttCkptConfig(600, 32); < 600, 32, 0 > 1 row found.
Notes
By default, TimesTen performs background checkpoints at regular intervals.
In the case that your application attempts to perform a checkpoint operation while a backup is in process, the backup waits until the checkpoint finishes. Regardless of whether the checkpoint is a background checkpoint or an application-requested checkpoint, the behavior is:
-
If a backup or checkpoint is running and you try to do a backup, it waits for the running backup or checkpoint to finish.
-
If a backup or checkpoint is running and you try to do a checkpoint, it does not wait. It returns an error immediately.
To turn off background checkpointing, set CkptFrequency
=0
and CkptLogVolume
=0
.
See Also