How to extract the hints we need from a SQL Query.

Let's say you have a SQL query running in one database and you need to run it in another similar one with the same execution plan perhaps only
once just to see its behaviour. Let's say you think "Hey, I could do it if I had the appropiate hints". But you do not know for sure
which hints exactly use. Here is a way to retrieve them!:

Troubleshooting a slow RMAN backup

(As I always do, the names of the databases and files are not the real ones, but the numbers are).

Yesterday we got a complain for one client. He said that the RMAN backup of the database was running on working hours and that should not be. I looked at the times of the backup along the week and saw that the backup took much longer than expected.

Recovering a deleted datafile using lsof

Here is a little trick that can be useful in case of a accidental delete of one datafile.
I do not recommend or encourage anyone to do it, but could be useful under certain specific situations.

How to find out what is consuming all of my bandwidth

Some days ago we received a complain from the networking department stating that some connections from one of our database servers were consuming most of the available bandwidth.
Obviously, the highest chance was that it was an oracle process, more, because it was our server who was sending the data, and the only applicacion in this server is Oracle.

Mapping a process in a remote server to a oracle session

Something we have probably needed many times is to find in a remote server the program that is running a session against our database.
Perhaps and for any reason,  we need to know exactly which concrete process in the remote server is accessing our database (from the
operating system perspective).
Let's say is a sqlplus prompt, but when we log on the remote system, we see that there are many sqlplus processes runnning. Which
is the right one?

Who And What SQL Is Using Temp Segments ?

Recently I came across an incident related to temporary segments. When I checked the view V$SORT_USAGE to take a look at what was using my temporary tablespace, I got shocked to see a query of the type "select 1 from dual". Obviously, this query does not do any kind of sort!

So I decided to take a close look at the issue.

First thing I noticed:

ORA-00030, 00000, "user session ID does not exist"

I think it's worth to write a short entry in my blog regards to it. That happened to me some days ago. First time I met this issue.

We were told that a session was blocking another session and preventing it to run a DELETE on one table. Up to this point, everything is normal. I ran an ALTER SYSTEM KILL SESSION.. on the blocking session, and, to my surprise, appeared this message: