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SAP® MaxDB - Log Area Full

 

 

Moderators: Christiane Hienger

WIKI Space Editor: Christiane Hienger, Thiago Lüttig.

This section explains how you can handle a log full situation and how you can prevent it.

Symptom
  • Symptom: Log Area Full (warning)

    If the log area is full (no space left on the log volumes), the application is suspended - you don't see any progress anymore. All database tasks are suspended until old log entries can be overwritten.

Solution of Log Full situations
(tick) Create a log backup 

When the log area is full, you have to create a log backup.
(thumbs up) Database Studio -> Administration Tasks -> Backup -> Log Backup

When a log backup has been created, the old log entries can be overwritten on the log volume. The suspended tasks are resumed, when the first log segment is written to the backup medium.

(warning) Adding a log volume never solve a log full situation! (sad)

Prevention
(smile) Activate the automatic log backup

To prevent a database standstill caused by a log full situation, you can activate the automatic log backup. If the automatic log backup is activated, a log backup is automatically performed, whenever a log segment is full.

Additional Useful Information
Relevant Training
Details

KnlMsg

The system writes messages into file KnlMsg/knldiag even before a filling level of 100% is reached:

 

Thread     0x2830 Task      1  2016-02-03 12:04:24     KernelDBE_ 20004:   75 percent of log area occupied, 6744 pages used
Thread     0x2830 Task      1  2016-02-03 12:04:24 WNG KernelDBE_ 20001:   90 percent of log area occupied, 8093 pages used
Thread     0x2830 Task      1  2016-02-03 12:04:24 WNG KernelDBE_ 20001:   95 percent of log area occupied, 8543 pages used
Thread     0x2830 Task      1  2016-02-03 12:04:24 WNG KernelDBE_ 20001:   96 percent of log area occupied, 8633 pages used
Thread     0x2830 Task      1  2016-02-03 12:04:24 WNG KernelDBE_ 20001:   97 percent of log area occupied, 8723 pages used
Thread     0x2830 Task      1  2016-02-03 12:04:24 WNG KernelDBE_ 20001:   98 percent of log area occupied, 8813 pages used
:
:
Thread     0x2B70 Task      2  2016-02-03 12:04:24     Log        20000:  Log is full.

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DatabaseStudio

In Database Studio select the database. Choose Administration -> Log Area.
You'll get the information about log full situation and a hint how to solve this log full situation.

Click on log backup brings you into the log backup menu.

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x_cons

The database console programm XCONS has to be started on operating system level. It shows the log full situation with the command x_cons <database_name> show act. If the log area is full, all active tasks are in state log full.


SERVERDB: MU790819
ID   UKT  Win   TASK       APPL Current        Timeout  Region     Wait UKT
          tid   type        pid state          Priority cnt try    item count
T19    8 0x1BCC User      13420 LOG FULL (246)          0               (s)4574

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db_cons

In Database Studio select the database. Choose Administration -> Command line. Enter db_cons show act to start the database console program XCONS as well. 
If the log area is full, all active tasks are in state log full.

 
SERVERDB: MU790819
ID   UKT  Win   TASK       APPL Current        Timeout  Region     Wait UKT
          tid   type        pid state          Priority cnt try    item count
T19    8 0x1BCC User      13420 LOG FULL (246)          0               (s)4574

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