Expert Oracle Exadata - Parent Directory

CHAPTER 12 MONITORING EXADATA PERFORMANCEthe session(s) of the problematic users’ applications or reports and drill down into what these sessionsare doing with ASH (which gives you the SQL_IDs of the top SQL statements for these sessions) andwhen needed, then drill down further into the top statements with SQL Monitoring reports.Monitoring SQL Statements with Real-Time SQLMonitoring ReportsWhen you click the SQL Monitoring link in the Enterprise Manager performance page, you will see thelatest monitored queries. The SQL Monitoring reports are present in Grid Control 11g R1 or 10g R5(10.2.0.5). If you are not using Grid Control, then you can either use the built-in Enterprise ManagerDatabase Console or run the SQL Monitoring reports manually from SQL*Plus as explained shortly. Notethat the SQL Monitoring feature requires Diagnostics and Tuning Pack licenses.Figure 12-1 shows the entry page to the SQL Monitoring reports. You can get there by clicking theSQL Monitoring link at the bottom of the Performance page in Grid Control. The SQL Monitoring page,as seen in Figure 12-1, lists the currently running, queued, and recently completed monitored SQLexecutions, with some key performance metrics and details, such as the degree of parallelism.Figure 12-1. Enterprise Manager’s overview of Monitored SQL ExecutionsThe Status column shows an icon with one of four statuses—running, done, error, or queued. When youclick the status icon, you will be taken to the SQL statement’s detailed monitoring page. One of the mostimportant pieces of information is the Duration column, showing how long a statement has been active.The duration is the wall-clock time from the start of the statement execution through the finish, or to thecurrent time in the event the statement is still executing. Figure 12-2 illustrates the difference betweenduration (wall-clock) and CPU time in statement execution.381