mattyoho

diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 2955ead3bb..01467628d8 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -348,7 +348,7 @@ def reorder!(*args) # :nodoc:
       self
     end
 
-    VALID_UNSCOPING_VALUES = Set.new([:where, :select, :group, :order, :lock,
+    VALID_UNSCOPING_VALUES = Set.new([:where, :select, :group, :order, :lock, :optimizer_hints,

mattyoho

package main

import (
	"fmt"
	"io"
	"os/exec"

	bf "gopkg.in/russross/blackfriday.v2"
)

mattyoho

Setup a Local Only Email Server (Linux, Unix, Mac)

1 - Point localhost.com to your machine

Most of programs will not accept an email using just @localhost as domain. So, edit /etc/hosts file to make the domain localhost.com point to your machine, including this content to the file:

127.0.0.1 localhost.com

2 - Install Postfix

mattyoho

Update

If you're looking at this in 2016 and beyond, I strongly recommend investigating real headless Chrome: https://chromium.googlesource.com/chromium/src/+/lkgr/headless/README.md

Windows and Mac users might find using Justin Ribeiro's Docker setup useful here while full support for these platforms is being worked out.

You can use chrome --headless on Linux as of M57 but note you'll need to build the binaries yourself for now.

The metabug for adding headless mode to Chromium is over here.

mattyoho

1. General Background and Overview

• Probabilistic Data Structures for Web Analytics and Data Mining : A great overview of the space of probabilistic data structures and how they are used in approximation algorithm implementation.
• Models and Issues in Data Stream Systems
• Philippe Flajolet’s contribution to streaming algorithms : A presentation by Jérémie Lumbroso that visits some of the hostorical perspectives and how it all began with Flajolet
• Approximate Frequency Counts over Data Streams by Gurmeet Singh Manku & Rajeev Motwani : One of the early papers on the subject.
• [Methods for Finding Frequent Items in Data Streams](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.187.9800&rep

mattyoho

Latency Comparison Numbers
--------------------------
L1 cache reference                            0.5 ns
Branch mispredict                             5   ns
L2 cache reference                            7   ns             14x L1 cache
Mutex lock/unlock                            25   ns
Main memory reference                       100   ns             20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy              3,000   ns
Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
Read 4K randomly from SSD*              150,000   ns    0.15 ms

mattyoho

Passing TCP socket descriptors around

In linux, normally, it is impossible to "bind()" to the same TCP port twice. If you try to bind to the same port from second proces unix processes you'll see:

socket.error: [Errno 98] Address already in use

mattyoho

Thread #0 was switched to  125044 times
Thread #1 was switched to  124994 times
Thread #2 was switched to  124994 times
Thread #3 was switched to  124993 times
Thread #4 was switched to  124993 times
Thread #5 was switched to  124994 times
Thread #6 was switched to  124994 times
Thread #7 was switched to  124993 times

1,000,000 thread switches took 2.143874 seconds

mattyoho

#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>

#define CHECK(thing) if (!(thing)) { perror(#thing); exit(1); }
#define MAX_PAGE_IN 104857600

mattyoho

# This is a shell archive.  Remove anything before this line, then
# unpack it by saving it in a file and typing "sh file".  (Files
# unpacked will be owned by you and have default permissions.)
#
# This archive contains:
# Makefile ping.1 ping.c ping.shar newping.1 newping.c

echo x - Makefile
cat > "Makefile" << '//E*O*F Makefile//'
# Revised to compile under SunOS 4.1.x (no longer necessary to install