ssh tunnel set up

server:
edit the file /etc/ssh/sshd_config

check that port-forwarding has not been disabled server-wide in /etc/ssh/sshd_config verify that
AllowTcpForwarding is set to yes (default setting is yes)

client:
use the following syntax
ssh -L localPort:remoteHost:RemoteHostPort sshServerHost

JVM monitoring

this is an example of how to monitoring the execution of a JVM running JBoss 4.2.3 GA under Solaris OS:

1. set the following Java options in run.conf (if you are on Windows, set them in run.bat)
JAVA_OPTS="....... -XX:+HeapDumpOnOutOfMemoryError -Dcom.sun.management.jmxremote.port=9999 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Djboss.platform.mbeanserver -Djavax.management.builder.initial=org.jboss.system.server.jmx.MBeanServerBuilderImpl -Djava.rmi.server.hostname= ............"
2. use jvisualvm.exe in your JDK to attach to the remote JBoss: Remote -> Add Remote Host -> add JMX connection -> :9999
3. run the following script on the server, to get memory utilization percentages:

pid=`/bin/jps -l | grep Main | awk {'print $1'
}`
/bin/jstat -gcutil $pid 2000

extract Java stack traces from log4j logs

here is described a solution to retrieve from a Windows machine any errors and stack traces in log4j log files saved on a Solaris machine.
Results are filtered out by a given date, in this example 2011-06-16

1. download plink.exe and put in a new folder
2. in the same folder create a batch file with the following content

@echo off
plink.exe -v -ssh 127.0.0.1 -P 24 -l username -pw password -m cmd.txt > output.txt

3. in the same folder create the file cmd.txt with the following content

for file in `find logFolder -name "logfile.log*" -print`
do
echo $file
awk '{ if(($1 == "2011-06-16") && ($4 == "ERROR")){print $0; gl = getline row; while(gl > 0 && row !~ /^[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]/){print row; gl = getline row;}} }' $file
done


Oracle, table size

The following query (to be run as sys user) is useful to calculate the space used by all tables


SELECT OWNER,
OBJECT_NAME,
OBJECT_TYPE,
TABLESPACE_NAME,
NUM_ROWS,
SUM(KBYTES) KBYTES,
TO_CHAR(DECODE(NUM_ROWS, 0, 0, SUM(KBYTES) / (NUM_ROWS)), '9999.99') KB_ROW
FROM (SELECT LO.OWNER,
LO.TABLE_NAME AS OBJECT_NAME,
EX.SEGMENT_TYPE AS OBJECT_TYPE,
EX.TABLESPACE_NAME,
TS.NUM_ROWS AS NUM_ROWS,
ROUND((SUM(EX.BYTES) / 1024)) AS KBYTES
FROM DBA_EXTENTS EX
JOIN DBA_LOBS LO ON (EX.OWNER = LO.OWNER AND
EX.SEGMENT_NAME = LO.SEGMENT_NAME)
JOIN DBA_TAB_STATISTICS TS ON (LO.OWNER = TS.OWNER AND
LO.TABLE_NAME = TS.TABLE_NAME)
GROUP BY LO.OWNER,
LO.TABLE_NAME,
LO.COLUMN_NAME,
EX.SEGMENT_NAME,
EX.SEGMENT_TYPE,
EX.TABLESPACE_NAME,
TS.NUM_ROWS
UNION ALL
SELECT EX.OWNER,
EX.SEGMENT_NAME AS OBJECT_NAME,
EX.SEGMENT_TYPE AS OBJECT_TYPE,
EX.TABLESPACE_NAME,
TS.NUM_ROWS,
ROUND((SUM(EX.BYTES) / 1024)) AS KBYTES
FROM DBA_EXTENTS EX
LEFT JOIN DBA_LOBS LO ON EX.OWNER = LO.OWNER
AND EX.SEGMENT_NAME = LO.SEGMENT_NAME
JOIN DBA_TAB_STATISTICS TS ON EX.OWNER = TS.OWNER
AND EX.SEGMENT_NAME = TS.TABLE_NAME
GROUP BY EX.OWNER,
EX.SEGMENT_NAME,
EX.SEGMENT_TYPE,
EX.TABLESPACE_NAME,
TS.NUM_ROWS)
WHERE OWNER LIKE 'CF%'
GROUP BY OWNER, OBJECT_NAME, OBJECT_TYPE, TABLESPACE_NAME, NUM_ROWS
ORDER BY KBYTES DESC;