just3ws

Postgres EXPLAIN Lunch & Learn @ BenchPrep

EXPLAIN Explained video on YouTube

What EXPLAIN doesn't do

• Tell you why a particular index isn't used
• Explain how to rewrite your queries
• Show what other factors make the DB slow
• Tell you how much time the request took outside the DB

just3ws

explain (analyze on, buffers on, verbose on, timing on)
select l.id, l.simulation_id, l.user_id, l.content_package_id, l.score, l.result, l.total_time_taken, l.created_at, l.updated_at
from simulation_results l
inner join (
  select simulation_id, max(created_at) created_at
  from simulation_results
  where user_id = 827911
  group by simulation_id
) r
on l.simulation_id = r.simulation_id and l.created_at = r.created_at

just3ws

ruby -W2 -v -e '                                                                                                                                                                                     (ruby-2.2.2@benchprep) wip-simulation-endpoints 9a603b95e ✗
puts "before"
module Foo
  puts "- Foo -"
end

puts "more"
module Foo::Bar
  puts "- Foo::Bar -"
end

just3ws

echo "BEGIN updating: $(pwd)"

cd "$1/.."

git fetch --all --prune --verbose

[[ -a Gemfile && "$(gem query --installed '^bundler$')" == 'false' ]] && gem install bundler --no-document

bundle check || bundle install

just3ws

brew tap homebrew/versions
brew install v8-315
brew unlink v8-315 && brew link v8-315
brew link --force v8-315
bundle config --global build.libv8 --with-system-v8
bundle install --full-index --jobs 4 --clean

just3ws

# Simple logger
logger = Logger.new(STDOUT)

# Some object
Foo = Struct.new(:hello, :goodbye)

foo = Foo.new
foo.hello = 'Hola'
foo.goodbye = 'Adiós'

just3ws

require 'forwardable'

class Said
  attr_reader :msg

  def initialize(msg = nil)
    @msg = (msg || '').freeze
  end

  def loud_enough?

just3ws

puts "<< De Morgan's laws >>\n\n"

PAIRS = [
  [false, true],
  [true, false],
  [true,  true],
  [false, false]
]

puts "\"NOT (A AND B)\" is the same as \"(NOT A) OR (NOT B)\""

just3ws

The original works were financially inert. They were posted out on the web for anyone to see them. 

An artist sees the works, likes them.

Takes those selected works, enlarges, fine-tunes, prints, frames, and displays the works inside a context.

The artist then puts those pieces on display and for sale.

What is for sale? 

just3ws

git-assume-unchangeable () {
 git update-index --assume-unchanged "$@"
}

git-assume-changeable () {
 git update-index --no-assume-unchanged "$@"
}

git-show-unchangeable () {
  git ls-files -v | grep -e "^[hsmrck]"