Oracle JDK : how to create deb

http://www.santasoft.it/en/blog/20120910_flash-install-oracle-java-7-jdk-debian-way :

sudo apt-get install java-package

Download JDK tar.gz from Oracle's website:
http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html

fakeroot make-jpkg jdk-7u60-linux-x64.tar.gz

A deb file is created in the same directory. Install the created deb file using
sudo dpkg -i oracle-j2sdk1.7_1.7.0+update60_amd64.deb

 sudo update-alternatives --config java

Other references:
https://wiki.debian.org/JavaPackage

oracle-jdk-7 403 forbidden or The request or reply is too large

While trying to install cloudera manager I keep getting 403 Forbidden when it tries to install oracle-jdk -7.
When  I tried downloading the file manually I kept getting "The request or reply is too large."

1. One potential solution:
http://askubuntu.com/questions/453367/download-failed-oracle-jdk-7-is-not-installed

after getting error 403, use ls:

ls /var/cache/oracle-jdk7-installer/

download the JDK tar.gz from someplace else on web (google archive filename) and compare its md5 checksum against the one given on oracle's website.

sudo cp ~/Downloads/jdk-7u55-linux-x64.tar.gz /var/cache/oracle-jdk7-installer/

sudo apt-get install oracle-java7-installer

2. Found out why it was happening:
The local network went through squid proxy that had a 100MB limit. The JDK archive is 130+ MB
Moved to another network and it started installing :P

Mysql select filter by partition - partition by date

Mysql 5.6 supports PARTITION clause in the query itself.
Mysql 5.5 relies on something called as partition pruning.

>show create table mytable
`id` int(11) NOT NULL AUTO_INCREMENT,
`created_at` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
...

PARTITION BY LIST (DAYOFMONTH(created_at))
(PARTITION day1 VALUES IN (1) ENGINE = InnoDB,
 PARTITION day2 VALUES IN (2) ENGINE = InnoDB,
...
PARTITION day31 VALUES IN (31) ENGINE = InnoDB)


explain partitions select count(*) from mytable where created_at = '2014-06-19'
explain partitions select count(*) from mytable where creation_date between '2014-06-19' and '2014-06-19'
Uses partition day19
Returns only those rows that have created_at  exactly equal to 2014-06-19 00:00:00'

explain partitions select count(*) from mytable where date(created_at) = '2014-06-19'

Correctly returns all rows of 19th June

But uses all partitions day1 to day31. Apparently this happens if you use any function on the LHS the where clause.

explain partitions  select count(*) from mytable where timestamp >= '2014-05-13' and time
stamp <= '2014-05-14';
Uses all partitions. Fails to prune partitions. All rows of 13th May.

Obviously I am screwed. Relying on indices for any performance improvement.
Apparently designing partitions on date has this drawback where your actual cell value is more granular than your partition definition. Here my actual value are timestamps accurate to seconds while my partition is defined on day of month(1-31).

This was used to leverage faster purging of data by truncating day-wise partitions. However leveraging any form of performance improvement on select queries seems impossible.

linux screen set session title and window after creating a session

http://stackoverflow.com/questions/3202111/set-a-name-for-screens-with-the-screen-command

Session title:
"Ctrl+A" -> ":"
type in "sessionname ABCD"
Visible when you do screen -ls

Window title:
"Ctrl+A" -> "Shift+A"
type in a title
Visible when you do CtlrA->Shift[double quote]

Setup Local Radio using VLC

Following are steps to setup a radio-like streaming on a LAN:
Works for sure on Ubuntu 12.10

I] Start VLC from command  line as follows:
vlc -vvv --sout-keep --sout '#standard{access=http,mux=ts,dst={YOUR OWN_LOCAL_IP_ADDRESS}:8080}'

II] Enqueue songs and hit play. You should see the seek bar moving.

III] Create a file "myliveradio.m3u" and put the following contents into it:

#EXTM3U
#EXTINF:-1,Radio Local - AACPlus - 32kbps Stream
http://{YOUR OWN_LOCAL_IP_ADDRESS}:8080


 IV]
Send this file to listeners. Anyone who opens this file in VLC woul start listening to the songs playing in your VLC. Please note that you won't be able to listen to the songs being streamed from the VLC process/window that's streaming them.
You yourself should open the file in a new VLC window and you can listen.

Source: http://forum.videolan.org/viewtopic.php?f=4&t=84303

Android device screencast on my computer

I have an android app that communicates with a server.
Wanted to present a demo of integration of the app with my servers.

For
Used the following tool to cast the device's screen on my PC. Was farely easy.

https://code.google.com/p/androidscreencast/

Needed to enable developer options on the device(Jelly Bean) for the same.
Developer options are not visible by default. To expose them tap SEVEN times on
Settings->About Phone ->Build Number
as suggested by: http://forum.xda-developers.com/showthread.php?t=1989777

However couldn't control the device by KB/MOUSE. Didn't have time to look into it further.

Ubuntu - install an older package from some repository ( puppet 0.25.4 on Ubuntu 12.10)

Case: Needed to install puppet version 0.25.4. on a latest version 1.10 of Ubuntu. Latest version of puppet- 3.X gets installed by default.

Found the deb for the version I need in following repository:
http://security.ubuntu.com/ubuntu/pool/main/p/puppet/puppet_0.25.4-2ubuntu6_all.deb

Following worked(as root):
echo "deb http://security.ubuntu.com/ubuntu lucid-security main\ndeb-src http://security.ubuntu.com/ubuntu lucid-security main"\
 >> /etc/apt/sources.list
apt-get update
apt-get install puppet-common=0.25.4-2ubuntu6.8 || exit
apt-get install puppet=0.25.4-2ubuntu6.8 || exit