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6to4: Easing the IPv6 transition

With the exhaustion of IPv4 address space looming sometime in 2012; probably earlier rather than later, it makes sense to ease on into IPv6 land.  Without straying into tunnel broking and endpoint shenanigans 6to4 is a method of wrapping up IPv6 inside of IPv4.

(note that MySQL does not currently support IPv6 itself – but what we’re discussing here is about externally facing systems, like your web/application servers)

6to4 performs three functions:

  1. Allocates an IPv6 address block to any host/network that has a global IPv4 address.
  2. Wraps up IPv6 packets inside IPv4 packets for transmission over IPv4 using 6in4 (traffic is sent over IPv4 inside IPv4 packets whose IP headers have the IP protocol number  set to 41; IPv6-in-IPv4. )  …
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Slapping MySQL-Proxy

I have old applications that need to read (and write) MyISAM tables that themselves receive lots of bulk updates. Time to try MySQL-Proxy.

MySQL Proxy is light on documentation and very few people written anything about working.   Most of what I have read says MySQL-Proxy is not ready for prim time.  I have hope so I had to give it a try.

I started with thee VMware servers. I setup one master and two read only slaves.   I tested the replication with mysqlslap from another independent server and it worked fine.  The slave never ran more then a second behind.

I downloaded mysql-proxy-0.8.0.tar.gz (64x version).  I …

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Lock-free vs. wait-free concurrency

There are two types of non-blocking thread synchronization algorithms - lock-free, and wait-free. Their meaning is often confused. In lock-free systems, while any particular computation may be blocked for some period of time, all CPUs are able to continue performing other computations. To put it differently, while a given thread might be blocked by other threads in a lock-free system, all CPUs can continue doing other useful work without stalls. Lock-free algorithms increase the overall throughput of a system by occassionally increasing the latency of a particular transaction. Most high-end database systems are based on lock-free algorithms, to varying degrees.

By contrast, wait-free algorithms ensure that in addition to all CPUs continuing to do useful work, no computation can ever be blocked by another computation. Wait-free algorithms have stronger …

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Maria Engine Performance once again

Note: Article has been edited as I was confusing MarisDB and the Maria Stoare Engine!

Just for the heck of it, I decided to try a very simple benchmark on the Maria Storage Engine again. This time, I'm using a simple SELECT. The table I use looks like this:
CREATE TABLE `t1` (
`c1` int(11) NOT NULL AUTO_INCREMENT,
`c2` char(100) DEFAULT NULL,
PRIMARY KEY (`c1`)
);
Which should be simple enough. I fill this with 1.3 millions rows, with c1 having consequitive numbers from 1 and up. My benchmark consists of random SELECTs of the c2 column from this table, using a primary key lookup on c1. I run this on 400 concurrent threads with each thread doing 1000 SELECTs. Ignoring the actual values, MyISAM and InnoDB come out pretty close in performance, with InnoDB slightly behind. Which is reasonable. Maria is at less than half the performance of MyISAM though. This is worrying. And I know what you say, …

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MySQL Sandbox embraces Python and meets Cluster
If you have tried Quick start guides: MySQL cluster in 10 minutes, you may have realized that it is really quick and easy.
However, it leaves some typing to be done.
Users of MySQL Sandbox have a horror of repetitive typing, and this got me thinking. "Could I integrate MySQL Sandbox and Cluster?"
The answer was: "Sure."
But then I started thinking of all the minor and major changes that I wanted to do to the Sandbox and have delayed for too long. What I need, is a radical refactoring.
And then I remembered that it has been almost two years since I learned a new programming language and that perhaps I could expand my horizons …
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MySQL Idiosyncrasies That Bite

The following are my slides that I presented at ODTUG Kaleidoscope 2010. This presentation talks about the MySQL defaults including a non-transactional state, silent data truncations, date management, and transaction isolation options. These are all critical for data integrity and consistency. I also cover in-depth topics including SQL_MODE, character sets and collations.

MySQL Idiosyncrasies That Bite View more presentations from Ronald Bradford.

Supreme Court sidesteps software patent issue

The court rejects one particular patent but doesn't provide new guidance about what types of business methods and software are patentable.

Lock-free vs. wait-free concurrency

There are two types of non-blocking thread synchronization algorithms – lock-free, and wait-free. Their meaning is often confused. In lock-free systems, while any particular computation may be blocked for some period of time, all CPUs are able to continue performing other computations. To put it differently, while a given thread might be blocked by other threads in a lock-free system, all CPUs can continue doing other useful work without stalls. Lock-free algorithms increase the overall throughput of a system by occassionally increasing the latency of a particular transaction. Most high-end database systems are based on lock-free algorithms, to varying degrees.

By contrast, wait-free algorithms ensure that in addition to all CPUs continuing to do useful work, no computation can ever be blocked by another computation. Wait-free algorithms have …

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eReaders and the Danger of Price Wars


 
A longer version of this story is published at www.opensources.com

Last week, Barnes & Noble announced they would cut the price on their wireless Nook eReader, from $259 to $199 ($149 for a new WiFi-only edition.)  Many thought this was a good opportunity for the third place contender to gain market share.  But within a few hours Amazon beat Barnes & Noble's price by $10, marking down the Kindle

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MySQL’s SQL Deviations and Extensions

Today at Kaleidoscope I will be doing a 90-minute session comparing MySQL’s SQL syntax to the ANSI/ISO SQL:2003 standard, entitled What Do You Mean, “SQL Syntax Error”?

You can download the PDF slides now.

For those that may be following along the presentation later today (4 pm Eastern time), here are some links that I may throw out during the session:

  • SQL 2003 standard – actually it is “Information taken from the Final Committee Draft (FCD) of ISO/IEC 9075-2:2003″ but it’s extremely close to the actual standard. The actual standard is a document that costs a non-trivial amount of money to get, and cannot be republished.
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