mustafaturan

Sample config for 2 million web socket connection

    sysctl -w fs.file-max=12000500
    sysctl -w fs.nr_open=20000500
    # Set the maximum number of open file descriptors
    ulimit -n 20000000

    # Set the memory size for TCP with minimum, default and maximum thresholds 
 sysctl -w net.ipv4.tcp_mem='10000000 10000000 10000000'

mlomnicki

require 'json'
require 'ostruct'

data = '{"a": {"b": 1}}'
result = JSON.parse(data, object_class: OpenStruct)
result.a.b # => 1

paulirish

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

Integralist

Lambda: standard

# Creating a lambda
l = lambda { |name| "Hi #{name}!" }

# Executing the lambda
l.call("foo") # => Hi foo!

rgreenjr

-- 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%' 

carlos8f

Mac OS X has only 16K ports available that won't be released until socket
TIME_WAIT is passed. The default timeout for TIME_WAIT is 15 seconds.
Consider reducing in case of available port bottleneck.

You can check whether this is a problem with netstat:

    # sysctl net.inet.tcp.msl
    net.inet.tcp.msl: 15000

    # sudo sysctl -w net.inet.tcp.msl=100

dhh

# autoload concerns
module YourApp
  class Application < Rails::Application
    config.autoload_paths += %W(
      #{config.root}/app/controllers/concerns
      #{config.root}/app/models/concerns
    )
  end
end

ahoward

BEGIN {

  require 'net/http'
  
  Net::HTTP.module_eval do
    alias_method '__initialize__', 'initialize'
    
    def initialize(*args,&block)
      __initialize__(*args, &block)