rapimo

get https://github.com/gregs1104/pgtune
see http://www.postgresql.org/docs/8.4/static/kernel-resources.html for reasonable kernel conf

play around with kernel settings without restart

    sudo sysctl -w kern.sysv.shmmax=4409466880 #4GB must be a multiplier of 4096
    kern.sysv.shmmax: 4194304 -> 1073741824

shmall must be shmax / pagesize
get pagesize with

rapimo

Select (SELECT hstore(array_agg(v), array_agg(c::text)) FROM (
  SELECT v, COUNT(*) as c from unnest(array_agg(country)) v GROUP BY v) t 
 ) countries FROM test;

-- =>  "de"=>"10669", "en"=>"21542", "fr"=>"21573", "it"=>"10783", "us"=>"21774"

rapimo

module ActiveRecord
  module NullObject #:nodoc:
    module InstanceMethods
        # should quark like a nil
        def nil?
          true
        end

        def present?
          false

rapimo

SELECT hstore(array_agg(v), array_agg(c::text)) FROM (
SELECT v, COUNT(*) as c ,1 as agg from  unnest(ARRAY['foo','bar','baz','foo']) v GROUP BY v) t
GROUP BY agg

--> "bar"=>"1", "baz"=>"1", "foo"=>"2"

rapimo

SELECT idstat.relname AS table_name, 
    indexrelname AS index_name, 
    idstat.idx_scan AS times_used,
pg_size_pretty(pg_relation_size(idstat.relname::regclass)) AS table_size,	pg_size_pretty(pg_relation_size(indexrelname::regclass)) AS index_size,
    n_tup_upd + n_tup_ins + n_tup_del as num_writes,
    indexdef AS definition
FROM pg_stat_user_indexes AS idstat JOIN pg_indexes ON indexrelname = indexname
    JOIN pg_stat_user_tables AS tabstat ON idstat.relname = tabstat.relname
WHERE idstat.idx_scan < 200
    AND indexdef !~* 'unique'

rapimo

-- Postgres makes it difficult four you to shoot yourselves in the foot
-- So it is not allowed to delete template databases
UPDATE pg_database SET datistemplate = FALSE where datname = 'template1';
DROP DATABASE template1;
CREATE DATABASE template1 WITH template = template0 encoding = 'utf8';
UPDATE pg_database SET datistemplate = TRUE where datname = 'template1';

rapimo

class Array
  #  [1,2,3].add [1,2,3] => [2, 4, 6]
  def add (other)
    self.zip(other).map{|a| a.inject(0){|s,n| s+=n || 0;s }}
  end
end

rapimo

require "benchmark"

class Cracker
  
  class << self  
  
    ## runs the code retuning sek runtime
    def run(test)
      Benchmark.realtime{`./crackme #{test}`}
    end

rapimo

cat /var/log/mail.log | grep "status=sent" | awk '{print $7}' | awk '{ sub(/^to=</, ""); print }' | awk '{ sub(/>,$/, ""); print }'

rapimo

-- ~/Library/Application\ Support/iTerm/Scripts/setup_rails.scpt
-- Thanks to http://www.worldgoneweb.com/2011/iterm2-advanced-features/#comment-20560
-- http://www.iterm2.com/#/section/documentation/scripting
tell application "iTerm" 
        activate
	set myterm to (make new terminal)
	set cd_to_my_project_path to ("cd ~/Projekte/my_awesome_project")
--	you can altenativly tell the first terminal		
        tell the first terminal			
		launch session "Panes"