wvengen

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

RadhikaG

def parent(i):
    return i/2

def left(i):
    return 2*i

def right(i):
    return (2*i + 1)

class Heap:

RadhikaG

global heap
global currSize

def parent(i): #returns parent index of ith index
    return i/2

def left(i): #returns left child of ith index
    return 2*i

def right(i): #returns right child of ith index

ChuckJHardy

class MyJob < ActiveJob::Base
  queue_as :urgent

  rescue_from(NoResultsError) do
    retry_job wait: 5.minutes, queue: :default
  end

  def perform(*args)
    MyService.call(*args)
  end

pixeltrix

When should you use DateTime and when should you use Time?

It's a common misconception that [William Shakespeare][1] and [Miguel de Cervantes][2] died on the same day in history - so much so that UNESCO named April 23 as [World Book Day because of this fact][3]. However because England hadn't yet adopted [Gregorian Calendar Reform][4] (and wouldn't until [1752][5]) their deaths are actually 10 days apart. Since Ruby's Time class implements a [proleptic Gregorian calendar][6] and has no concept of calendar reform then there's no way to express this. This is where DateTime steps in:

>> shakespeare = DateTime.iso8601('1616-04-23', Date::ENGLAND)
=> Tue, 23 Apr 1616 00:00:00 +0000
>> cervantes = DateTime.iso8601('1616-04-23', Date::ITALY)
=> Sat, 23 Apr 1616 00:00:00 +0000

janko

require "active_record"

ActiveRecord::Base.establish_connection('postgres:///testing')
ActiveRecord::Migration.verbose = false

ActiveRecord::Migration.class_eval do
  create_table :played_quizzes, force: true do |t|
    t.integer :player_ids, array: true
    t.json    :quiz_snapshot
  end

mr-linch

#!/usr/bin/env python3

import csv
import urllib.request

from bs4 import BeautifulSoup


BASE_URL = 'http://www.weblancer.net/projects/'

lolzballs

import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;

public class HelloWorld{
	private static HelloWorld instance;
    public static void main(String[] args){
        instantiateHelloWorldMainClassAndRun();

itsthatguy

# Run the following command in shell:
# curl -s https://gist.githubusercontent.com/itsthatguy/48d9b47dba05b300c65b/raw/80b1111bb5273697d1db4f5662eb763aa4a80cdc/foo.coffee | coffee --stdio
class Foo
  name: 'abott'
  @myFunction: ->
    console.log "\n# start"
    console.log "\nFoo"
    console.log "this.name:", this.name
  myOtherFunction: ->
    console.log "\nfoo (instance of Foo)"

solnic

REQUIRE_DATA = {}
BUNDLED_GEMS = `bundle show | grep "*" | awk '{print $2}'`.split("\n").sort
require 'bigdecimal'

def require(name)
  start = Time.now
  ret = super
  stop = Time.now
  total = BigDecimal(stop-start, 6)
  REQUIRE_DATA[name] = total if BUNDLED_GEMS.include?(name)