Simulating V$KERNEL_IO_OUTLIER on LINUX using Systemtap

With the 12C version oracle come with many amazing feature, one of them is the integration of ORACLE database with the awesome dynamic tracing framework  DTRACE on SOLARIS system.In fact we can see this in action using  V$KERNEL_IO_OUTLIER view.Like explained by Andrey Nikolaev in  https://andreynikolaev.wordpress.com/2013/09/20/vkernel_io_outlier/ this view is based on a DTrace script running in the background.He also managed to rewrite the script so it can be used also on pre-12c Oracle databases.(That’s cool !!)

But what About Linux system ?

Continue reading

Analyzing performance of an ORACLE database using perf (perf_events) on VMWARE

Some times we need to deeg deeper to understand what’s going on. Recently i was faced with a problem to tune a session consuming a lot of CPU power, so i begin by analysing the session stats and to get more info i decided to use the perf tools on the system level but it gives me nothing. After some checks it appears that the system was running on a virtual machine.

Continue reading