Tuning redo logs

In this recipe, we will see how to monitor redo logs.

How to do it...

The following steps will demonstrate monitoring of redo logs:

1. Connect to the database as SYSDBA:

   CONNECT / AS SYSDBA
   

2. Verify possible problems by inspecting the V$SYSTEM_EVENT dynamic performance view:

   SELECT EVENT, TOTAL_WAITS, TIME_WAITED FROM V$SYSTEM_EVENT
   WHERE EVENT LIKE 'log file%';
   

3. Query the data dictionary about the redo log files:

   COL MEMBER FOR A40
   SELECT * FROM V$LOGFILE;
   CLEAR COL
   

4. Query the data dictionary about redo log details:

   SELECT * FROM V$LOG;
   

5. Query the historical log switch data:

   SELECT * FROM V$LOG_HISTORY ORDER BY RECID;
   

How it works...

In step 2, we query the V$SYSTEM_EVENT dynamic performance view to inspect problems related to redo logs. In the following screenshot, we can see the results obtained on a test database:

The important events to be observed are log file sync and log file parallel write. Often, a high value for the latter statistic is not evidence of a problem. It indicates...