Displaying Log Area Information 

You can display information on the size and current usage of the log area in the Database Manager GUI.

Procedure

...

       1.      Select the required database instance in the list of database instances.
Connect to the DBM server for this database instance if necessary.

       2.      Choose Instance ® Information ® Log Area.

Result

The display is divided into the following areas:

·        Volumes: Information about the log volumes

·        Settings: Information about the log settings, values of the database parameters MAXLOGVOLUMES and LOG_SEGMENT_SIZE

·        Usage: Usage of the log area

·        I/O: Reads and writes for each log volume

·        Activity: Summary of the log activities

Volumes

Among other things, you see the following information for each log volume: name, size, type, and path in the run directory.

Settings

You can control redo log management by making various log settings. The following settings are displayed:

·        Log Mode: See Log Mode
SINGLE: The log volumes are not mirrored.
MIRRORED: The log volumes are mirrored.

·        Overwrite Mode: See Overwrite Mode for the Log Area
NORMAL: The log area cannot be overwritten until the log entries have been backed up.
OVERWRITE: The log area is overwritten when it is full.

·        Redo Log Management: See Activating or Deactivating Redo Log Management
ACTIVATED: Redo log management is activated.
DEACTIVATED: Redo log management is deactivated.

See also:

Changing Log Settings

The number of log volumes is controlled by the general database parameter MAXLOGVOLUMES. The general database parameter LOG_SEGMENT_SIZE controls the size of segment that is chosen when log backups are made. The current values of these database parameters are displayed.

Usage

If the database instance is in the ONLINE operational state, you can display the usage of the log area.

Total Size	Total size of the log area
Free Log Area	Free log area
Used Log Area	Used log area
Unsaved Log Area	Size of the log area that has not yet been backed up
Log since last data backup	Log entries written since the last data backup

I/O

If the database instance is in the ONLINE operational state, you can display the read and write activities for each log volume.

Activity

Log Pages Written	Written log pages
Wait for Log Writer	Indicates how often it was necessary to wait for a log entry to be written
Group Commits	Indicates how often more than one transaction had to wait for the I/O operation for a log page
Log I/O Queue Overflow	Indicates how often a transaction had to wait to write a log entry because the log queue was full