ryanermita

Optimistic Locking assumes that a database transaction conflict is very rare to happen. It uses a version number of the record to track the changes. It raise an error when other user tries to update the record while it is lock.

usage

Just add a lock_version column to the table you want to place the lock and Rails will automatically check this column before updating the record.

Pessimistic locking assumes that database transaction conflict is very likely to happen. It locks the record until the transaction is done. If the record is currently lock and the other user make a transaction, that second transaction will wait until the lock in first transaction is release.

usage

reinh

Priority Queues
═══════════════

  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
                   INSERT  DEL-MIN  MIN  DEC-KEY  DELETE  MERGE
   binary          log n   log n    1    log n    log n   n
   binomial        1       log n    1    log n    log n   log n
   Fibonacci       1       log n†   1    1†       log n†  log n
   Pairing         1†      log n†   1†   1†       log n†  1†
   Brodal-Okasaki  1       log n    1    1        log n   1

excid3

Realtime Notifications with ActionCable

In this episode we're going to be adding realtime notifications into your app using ActionCable. We've talked about notifications a few times in the past and we used AJAX polling for that. 95% of the time, polling is the solution that would be recommended for it.

But if you're looking for a good introduction into ActionCable then this is a decent one because we're only really using it for one way from the server side to the client side.

Getting started

So to get started we're starting with an app that has Bootstrap installed and then we created a Main controller with an index view which is where we will list our Notifications as for this example.

Before we generate our channels let's install a few things

sdogruyol

Crystal vs Node.js Websocket Benchmark

Crystal 0.9.1 with Kemal

require "kemal"

ws "/" do |socket|
  socket.on_message do |message|
 end

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

kodekracker

# -*- coding: utf-8 -*-

# Gunicorn(v19.3) Configuration File
# Reference - http://docs.gunicorn.org/en/19.3/settings.html
#
# To run gunicorn by using this config, run gunicorn by passing
# config file path, ex:
#
#       $ gunicorn --config=gunicorn.py MODULE_NAME:VARIABLE_NAME
#

notozeki

CRYSTAL = crystal
UNAME = "$(shell uname -ms)"
LIBRARY_PATH = $(shell brew --prefix crystal-lang)/embedded/lib
LIBS = -levent -lpcl -lpcre -lgc -lpthread
LDFLAGS = -Wl,-undefined,dynamic_lookup

TARGET = crystal_example_ext.bundle

$(TARGET): crystal_example_ext.o
	$(CC) -bundle -L$(LIBRARY_PATH) -o $@ $^ $(LIBS) $(LDFLAGS)

SamSaffron

# speed up pluck

class ActiveRecord::Relation

  class RailsDateTimeDecoder < PG::SimpleDecoder
    def decode(string, tuple=nil, field=nil)
      if Rails.version >= "4.2.0"
        @caster ||= ActiveRecord::Type::DateTime.new
        @caster.type_cast_from_database(string)
      else

kpiwko

#! /bin/sh
# TODO: parse & pass-through sudo options from $@
sudo_options="-E"
scls=$X_SCLS
#available_scls="`scl --list | tr '\n' ' ' | sed 's/ $//'`"

for arg in "$@"
do
   case "$arg" in
     *\'*)

jonathonbyrdziak

# ----------------------------------------------------------------------
# CORS-enabled images (@crossorigin)
# ----------------------------------------------------------------------
# Send CORS headers if browsers request them; enabled by default for images.
# developer.mozilla.org/en/CORS_Enabled_Image
# blog.chromium.org/2011/07/using-cross-domain-images-in-webgl-and.html
# hacks.mozilla.org/2011/11/using-cors-to-load-webgl-textures-from-cross-domain-images/
# wiki.mozilla.org/Security/Reviews/crossoriginAttribute
<IfModule mod_setenvif.c>
  <IfModule mod_headers.c>