MySQL, kernel_mutex, etc.

Vadim Tkachenko of Percona is playing with innodb_thread_concurrency:

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WAMP stacks reviewed

From Infoworld:

Review: WAMP stacks for Web developers

Created 2012-05-30 03:00AM

There are two places where I do software development for the Web. The first is “out there,” on the Web server for which I pay my monthly hosting fee. The second is “in here,” right on my own desktop, where I have a stand-alone Web development stack running side by side with everything else.

A stand-alone Web stack is a self-contained way to run the needed components for a Web application without requiring a separate machine or Web account, both of which typically mean extra dollars. Developers can prototype a project locally on such a stack, then deploy the results to a live remote server — or even convert the local stack into a live server, if they’re so inclined and the stack is designed for production use. If you’re a novice Web programmer, a local stack is a handy way to learn the ins and outs of programming for the Web in a controlled environment.

Linux users have the advantage of the Web stack being a native part of their environment, since Linux distributions aren’t as rigidly partitioned into “desktop” and “server” editions as Windows is — except in the sense of which components are installed by default. Windows users, though, have to install the entire stack from scratch. The good news is that all the pieces they’d need — Apache, MySQL, PHP, and so on — are available in Windows editions.

In this article I review five environments — AMPPS, BitNami WAMPStack, Microsoft Web Platform Installer, XAMPP, and WampServer — you can use to set up a local Web development server on a Windows box. These stacks contain all of the above-mentioned components (with IIS and SQL Server Express taking the place of Apache and MySQL in Microsoft’s offering) installed from a single executable or .MSI package, so each piece doesn’t need to be downloaded, installed, and configured separately. These Web server stacks also contain management tools for each separate component and for the stack as a whole, so you’re not stuck with the extra burden of having to manage the whole thing by hand. And they’re all free for the downloading.

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10 essential MySQL tools

From Infoworld:

10 essential MySQL tools for admins

Created 2011-08-01 03:00AM

MySQL is a complex system that requires many tools to repair, diagnose, and optimize it. Fortunately for admins, MySQL has attracted a vibrant community of developers who are putting out high-quality open source tools to help with the complexity, performance, and health of MySQL systems, most of which are available for free.

The following 10 open source tools are valuable resources for anyone using MySQL, from a stand-alone instance to a multiple-node environment. The list has been compiled with variety in mind. You will find tools to help back up MySQL data, increase performance, guard against data drift, and log pertinent troubleshooting data when problems arise.

There are several reasons why you should consider these tools instead of creating your own in-house tools. First, thanks to their wide use, they’re mature and field-tested. Second, because they are free and open source, they benefit from the knowledge and experience of the continually expanding MySQL community. Finally, these tools are actively developed, and many are professionally supported (either for free or commercially), so they continue to improve and adapt with the evolving MySQL industry.

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Piggybacking WordPress

Let’s say you’re running WordPress.  You use it extensively, your whole team is on it, you have some cool plugins that expand WordPress’ functionality, but now you need a whole different custom application (or five) to run alongside WordPress.  What you don’t need, however, is a second authentication system.  Luckily, you don’t have to have one; you can access WordPress’ authentication system, check the user’s authentication, and if there is none, redirect the user to WordPress login form, have them authenticated, and redirect them back to your application.

The following snippet does exactly that. Obviously, it doesn’t have a lot of functionality, it just outputs the current user’s data if the user is authenticated.  Note that in this example the code is located in a subdirectory of WordPress’ root directory (hence, the ../ in include ‘../wp-config.php’), but it should work from anywhere, as long as wp-config.php is reachable for inclusion.

include '../wp-config.php';
if ($current_user->ID == 0) {
  $location = 'Location: ' . site_url('')
    . '/wp-login.php?redirect_to='
    . urlencode($_SERVER['PHP_SELF']);
  echo "<p>You are not logged in.</p>\r\n";
} else {
  echo "<h2>WP: wp_get_current_user()</h2>\r\n";
  echo "<pre>";
  echo "</pre>\r\n";
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April Fool Day on

Here’s what looks like today:

Note the picture of camel.  I wonder if this is a joke by the server’s operators or a friendly prank by someone in the Perl community…

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A Quantum Theory of Mitt Romney

Generally, I tend to stay away from political commentary.  But this is way too funny, not to mention that it brings back fond memories of QED: The Strange Theory of Light and Matter

From New York Times: Continue reading

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An alternative to Google Maps

Here it is:

Played around with it, and it was very robust while showing San Francisco, but slowed down considerably when I tried Los Angeles.  Could it be that SF maps are cached server-side as SF is the default location displayed at the developer’s site?  Or could have been a one-time fluke after all…

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The latest on data breaches

The 2012 Verizon Data Breach Investigations Report is out.  I’d love a clarification though; what percentage of “outsider” attacks involved social engineering (including spear phishing)?

Verizon security report:
Hacktivism up, insider threats down

By InfoWorld Tech Watch
Created 2012-03-22 03:00AM

Over 855 data breaches resulting in the compromise of more than 174 million records around the world provided rich source material for the 2012 Verizon Data Breach Investigations Report, a highly respected analysis that includes data from the U.S. Secret Service, four other investigative agencies, and the telecom giant’s own vast trove of information.

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Private equity + foreclosure = 8%

Private Equity’s Foreclosures for Rentals Net 8%

By Edward Robinson – Mar 13, 2012
Bloomberg Markets Magazine

Ken Major climbs the steps of a county courthouse in a San Francisco suburb with $500,000 in cashier’s checks in one hand and a list of addresses in the other. Major is a buyer for Waypoint Real Estate Group LLC, an Oakland-based investment firm that’s scooping up foreclosed homes in California.

On this December afternoon, he joins a dozen house flippers as an auctioneer starts hawking the latest batch of defaulted properties to hit the market. Major bids on a three-bedroom house in Antioch, and after other buyers counter, he wins at $147,600.
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How much connectivity is too much?

From InfoWorld:

Researchers: Having too many connections weakens networks

By Joab Jackson

When it comes to connecting networks or other systems together, it is best to have many, but not too many, connections, mathematicians have found.

Administrators and network engineers have long assumed that the more connections they insert between multiple networks, the more resilient the communications between these networks will be. The Internet, for example, derives much of its resiliency from multiple, redundant links. But this is true only up to a point. Too many connections can actually be dangerous, because failures in one network can easily cascade to the other, noted Charles Brummitt, a mathematics researcher at the University of California, Davis, who led a team that looked into this issue.

Instead, network owners should fine-tune the number of connections for maximum resiliency, Brummitt said.

Brummitt’s team published its work in this week’s issue of the “Proceedings of The National Academies of Science.”

The work is a mathematical model of how a collection of systems works together. “We’re taking a larger view and studying networks of networks,” he said. Interconnected networks can be vulnerable to cascading failures, in which a failure, or overload, in one network can disrupt another network. In a typical scenario, when one network is overloaded, it will offload its traffic to the second network. But if a failure is enough to overwhelm the first network, it may overwhelm the second network as well.

“There are some benefits to opening connections to another network. When your network is under stress, the neighboring network can help you out. But in some cases, the neighboring network can be volatile and make your problems worse. There is a trade-off,” Brummitt said. “We are trying to measure this trade-off and find what amount of interdependence among different networks would minimize the risk of large, spreading failures.”

The study, also available in draft form (PDF) at ArXiv, primarily studied interlocked power grids but could apply to computer networks and interconnected computer systems as well, the authors note. The work could influence thinking on issues such as how to best deal with DDoS (distributed denial-of-service) attacks, which can take down individual servers and nearby routers, causing traffic to be rerouted to nearby networks. Balancing workloads across multiple cloud computing services could be another area where the work would apply.

“As a first theoretical step, it’s very nice work,” said Cris Moore, a professor in the computer science department at the University of New Mexico. Moore was not involved in the project. “They found a sweet spot in the middle,” between too much connectivity and not enough, he said. “If you have some interconnection between clusters but not too much, then [the clusters] can help each other bear a load, without causing avalanches [of work] sloshing back and forth.”

Of course, one of the largest networks of networks is the Internet. For the Internet, backbone providers peer with one another, or connect their networks together, which allows Internet traffic to move seamlessly from source to destination. Much has been made about the Internet’s natural resiliency in the face of disaster. But is it as resilient as it could be?

“That’s a thorny question,” Brummitt admitted. “I don’t think we are in a position to make any guesses. Even understanding the network structure of the Internet is a problem in itself. But the Internet has proved to be rather resilient. So far, it seems like the Internet is not too interdependent. But this is speculative.”

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