crmaxx

Finding a Ruby memory leak using a time analysis

When developing a program in Ruby, you may sometimes encounter a memory leak. For a while now, Ruby has a facility to gather information about what objects are laying around: ObjectSpace.

There are several approaches one can take to debug a leak. This discusses a time-based approach, where a full memory dump is generated every, say, 5 minutes, during a time that the memory leak is showing up. Afterwards, one can look at all the objects, and find out which ones are staying around, causing the

crmaxx

require "bigdecimal"

# List of our individual pricing rules
TAX           = ->(val) { val + val*0.05 }
FEE           = ->(val) { val + 1 }
PREMIUM       = ->(val) { val + 10 }
DISCOUNT      = ->(val) { val * 0.90 }
ROUND_TO_CENT = ->(val) { val.round(2) }
# One presenter
PRESENT       = ->(val) { val.to_f }

crmaxx

--[[
INSTALLATION (create directories if they don't exist):
- put the file in the VLC subdir /lua/extensions, by default:
* Windows (all users): %ProgramFiles%\VideoLAN\VLC\lua\extensions\
* Windows (current user): %APPDATA%\VLC\lua\extensions\
* Linux (all users): /usr/share/vlc/lua/extensions/
* Linux (current user): ~/.local/share/vlc/lua/extensions/
* Mac OS X (all users): /Applications/VLC.app/Contents/MacOS/share/lua/extensions/
- Restart VLC.
]]--

crmaxx

Installing Postgres via Brew

Pre-Reqs

Brew Package Manager

In your command-line run the following commands:

1. brew doctor
2. brew update

crmaxx

-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

crmaxx

# p4merge for 64 bit
wget https://cdist2.perforce.com/perforce/r18.2/bin.linux26x86_64/p4v.tgz

tar zxvf p4v.tgz
sudo cp -r p4v-* /usr/local/p4v/
sudo ln -s /usr/local/p4v/bin/p4merge /usr/local/bin/p4merge

crmaxx

require 'minitest/mock'
require 'minitest/unit'
require 'date'

MiniTest::Unit.autorun

class TestMailPurge < MiniTest::Unit::TestCase
  class MailPurge
    def initialize(imap)
      @imap = imap

crmaxx

#!/bin/bash

apt-get update
apt-get install -y apt-transport-https ca-certificates
apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D

echo 'deb https://apt.dockerproject.org/repo ubuntu-xenial main' > /etc/apt/sources.list.d/docker.list

apt-get update

crmaxx

# based on http://blogs.pdmlab.com/alexander.zeitler/articles/installing-and-configuring-p4merge-for-git-on-ubuntu/

$ cd ~/Downloads

$ wget https://cdist2.perforce.com/perforce/r18.2/bin.linux26x86_64/p4v.tgz

$ tar zxvf p4v.tgz

$ sudo mkdir /opt/p4v

crmaxx

sudo apt-get install git-core curl zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev \
             libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev software-properties-common \ 
             libffi-dev libgmp-dev libreadline6-dev ibgdbm-dev libncurses5-dev automake libtool bison

sudo apt-get install postgresql-10 postgresql-client-10 postgresql-contrib-10 libpq-dev

sudo -u postgres createuser crmaxx -s

# If you would like to set a password for the user, you can do the following
sudo -u postgres psql