In this blog post i wanted to test some of Dennis Yurichev findings described in “Oracle RDBMS rootkits and other modifications” in recent oracle database 18.104.22.168 (The same can be done with 12.2) .So the idea here is to inject a backdoor in oracle LISTENER so that we can access Linux shell remotely.
This is a short and quick note to show how we can enhance DBMS_OUTPUT capabilities using a small systemtap script without modifying the source code.Basically it will allow us to display the DBMS_OUTPUT message incrementally (the program don’t need to finish it’s execution) by attaching to an already running session (no need to enable DBMS_OUTPUT). The output can also be easily redirected to a file.
The idea is to try to access the function parameters.This can become complex in case of different arguments types and number but in our case there is only one argument of type varchar2.
This is a followup to my previous posts on Deeper look at CPU utilization :
- Deeper look at CPU utilization : The power of PMU events
- Deeper look at CPU utilization : TMAM Example
Following a comment from Kevin Closson here is the hierarchical execution cycles breakdown based on the TMAM method before and after enabling HUGEPAGES when running SLOB for testing Logical I/O.
This will let’s us identify our micro-architectural bottlenecks and correctly characterize the SLOB workloads ! Continue reading
This is a followup to my previous post on Deeper look at CPU utilization : The power of PMU events .
So let’s go back to my previous example using the General Exploration View of Intel VTune :
This blog post is about how to extend our capabilities to trace and profile PL/SQL code.It’s primarily motivated by few tweets from Franck Pachot and of course because it’s FUN !
So in the first part of this series we are going to answer to this questions : Can we map those underling function to the source PL/SQL object and line number ? Can we obtain a full trace ? Of course yes otherwise there will be no blog post :p
Here is the followup to my previous blog post Getting Latch holder info out of the state objects in SGA memory where i described how we can extract latch state objects directly from the SGA memory. So let’s begin !