Thread Contentions

http://www.ibm.com/developerworks/java/library/j-threads2/index.html

http://www.concentric.net/~ttwang/tech/syncbottle.htm

http://dev.blogs.nuxeo.com/2011/07/detecting-threads-contention.html


Well Eplained in Detail:
https://community.dynatrace.com/community/display/PUB/Identify+Thread+Contention+-+Guest+Article+by+Lucy+Monahan

Free Memory in Linux

Actual Free Memory in Linux = Free+ Buffer+Cache

Linux uses RAM to load the Disk data in RAM (emory) as reading data from memory is faster. As the needs for memory to other process increases it shrinks the cahced data accordingly.

http://blog.scoutapp.com/articles/2010/10/06/determining-free-memory-on-linux

Oracle Analytical functions

http://www.orafaq.com/node/55

calculate avg and 90th percentile from awk command

Average:

cat <filename> |grep HOME|grep "Number of samples"|awk -F "," '{sum+=$2} END { print "Average = ",sum/NR}'

95^th Percentile:

cat <filename> |grep HOME|grep "Number of samples"|awk -F "," '{print $2}' |sort -n|awk 'BEGIN{i=0} {s[i]=$1; i++;} END{print s[int(NR*0.95-0.5)]}'

calculate avg of a column

awk '{ s += $1 } END { print "sum: ", s, " average: ", s/NR, " samples: ", NR }' rails_production_log_or_whatever.log

AWk command to cut a big file into small files at a repeatative word

awk '/selected./{n++}{print >"out" n ".txt" }' partitionbased_cc_acc_ids.txt

here "selected." is the repeatative word..