Amit Chakradeo amit

I hereby claim:

To claim this, I am signing this object:

Migrating a Rails project from MySQL to PostgreSQL

This brief guide is written from my own experience with migrating a large (~5GB) MySQL database to PostgreSQL for a Rails project.

No warranties, guarantees, support etc. Use at your own risk and, as always, ENSURE YOU MAKE BACKUPS FIRST!

I chose [pgloader][1] because it's extremely fast. YMMV.

Replace mysql2 gem with pg in Gemfile.
Update config/database.yml for PostgreSQL. I used [Rails' template][2] as a starting point.

	threads = []
	(0..4).each do
	threads << Thread.new {
	row = XAuth::Variable.where(name: "current_member_id").first_or_create
	row.with_lock do
	sleep(2)
	oldvalue = row.value.to_i
	newvalue = oldvalue + 1
	row.value = newvalue
	row.save!

	#!/bin/bash
	# This script checks if the root user can access SSH server on this machine

	FILE="/etc/ssh/sshd_config"

	if ! [[ -r $FILE ]]
	then
	echo "Unable to read $FILE"
	exit 1
	fi

	require 'socket'
	require 'json'

	class AircraftPositionStream

	def initialize host, port
	@host = host
	@port = port
	end

	# Harshad numbers are divisible by sum of their digits. e.g. 1729 (1+7+2+9=19 and 19*91=1729
	# https://en.wikipedia.org/wiki/Harshad_number

	# Sum of digits of a (positive) number: q

	q = 987654321
	puts q.to_s.split('').reduce{\|sum, n\| sum.to_i + n.to_i}.to_i

	# Find Harshad number between 1 and 1000:
	puts (1..1000).select{\|q\| q % q.to_s.split('').reduce{\|sum, n\| sum.to_i + n.to_i}.to_i == 0}

	# apt install postgresql-client
	# apt-get -y install bash-completion wget
	# wget --no-check-certificate --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc \| apt-key add -
	# echo "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -cs`-pgdg main" \| sudo tee /etc/apt/sources.list.d/pgdg.list
	# apt-get update
	# apt-get -y install postgresql-client-12

	namespace :db do

	desc "Dumps the database to backups"