Killing all processes containing a specific pattern in their process name

Say you want to kill all processes spawned from your Oracle Home. In Linux/Unix there is a nice command that lets you achieve this very easily.

If your Oracle Home is /u01/app/oracleHome then any oracle related process will have oracleHome in it's name. To kill all such processes at once issue the command :

pkill -9 -f oracleHome

How to take a Java thread dump from a shell/bash script

We already know how to get a Java thread dump manually. But what if we want to take a Java thread dump from a script to help us automate things.

To do this we need to come up with a ps and grep combination that will only return one result. so grep as many times as neccessary and/or use keywords that are only found in your process name so you only get one result.

Remember to add [] somewhere in your first grep so grep doesn't matches itself.

output=$(ps -ef | grep m[y]ProcesseName )

Then all you need to do is sending the QUIT signal to $2 which stores the PID of your process.

kill -QUIT $2

So just add the above two lines to your script after modifying the first line to fit your needs and you should be good to go.

How to create a Java Thread dump

To create a java thread dump in Linux you must send a QUIT signal to your java process. JVM then catches that and prints the thread dump to standard output. If you are running your program from a script that has it's output directed to a file the thread dump will be written to that file obviously .

So first do we need to find the PID of our java program.

ps -ef | grep java

for example this could return :

lapps     3243  3065 21 Nov12 ?        08:01:50 java -Xms2048m -Xmx10g -XX:MaxPermSize=256m -Djava.awt.headless=true -XX:+UseParallelGC -XX:-UseGCOverheadLimit -classpath .:./test.jar:./lib/:./lib/* mypackage.org.TestApp

Now that we have 3243 as the PID, we simply send a QUIT signal to it.

kill -QUIT 3243

Kill connections to an Oracle Schema

You can kill all connections by running the code below. Just Replace SCHEMA with your schema name.

declare str varchar2(100);
begin
for SES in (select sid,serial# from v$session where username='SCHEMA'  )
loop
str := 'alter system disconnect session '|| '''' || to_char(SES.sid) ||','||to_char(SES.serial#)||'''' || ' ' || 'immediate';
execute immediate str;
end loop;
end;


To kill a single connection, first find the connection by running:

select * from v$session;

Then run:

alter system kill session 'sid,serial#';

where sid and serial# are extracted from your first query of v$session above.