Guest blogger Pamela Samuelson is the Richard M. Sherman Distinguished Professor of Law and Information at the University of California, Berkeley. She teaches courses on intellectual property, cyberlaw, and information privacy, and she has written and spoken extensively about the challenges that new information technologies pose for traditional legal regimes. A version of this material is scheduled to appear in the November 2010 issue of Communications of the ACM.

Two-thirds of the approximately 700 software entrepreneurs who participated in the 2008 Berkeley Patent Survey report that they neither have nor are seeking patents for innovations embodied in their products and services. These entrepreneurs rate patents as the least important mechanism among seven options for attaining competitive advantage in the marketplace. Even software startups that hold patents regard …

I started translation of Part 3 "Other cases". In this part I mostly describe how wrong settings can lead to misterious errors. First chapter in this part about large amount of data.

Part 3. Other cases.


Chapter 8. Large amount of data.

There are cases when query is just symptom of wrong behavior, but true reason is wrong settings.

One of the cases is too small max_allowed_packet for data sent. MySQL
server variable max_allowed_packet defines maximum possible amount of
data which MySQL server can receive or send. Amount of
max_allowed_packet is specified in bytes.

Error usually looks like:


$mysql51 test <phpconf2009_1.sql

ERROR 1153 (08S01) at line 33: Got a packet …

I am speaking in a few days at OSCON 2010 in Portland, Oregon. My talk, “MySQL Bottleneck Hunters – How Schooner Increased MySQL Performance by 8x” is about how Schooner optimized MySQL to run on modern hardware with flash memory. Come on by if you’re at OSCON!

Here’s the abstract:

MySQL Bottleneck Hunters – How Schooner Increased MySQL Performance by 8x — Thursday, July 22, 2010 at 11:30am

MySQL users have an insatiable need for speed, capacity, and availability, all at a reasonable cost. This session will provide technical overview of the approach that Schooner engineering took to optimize MySQL Enterprise and InnoDB with flash memory, multi-core processors, and DRAM to achieve an 8x …

It is easy for MySQL replication to become bottleneck when Master server is not seriously loaded and the more cores and hard drives the get the larger the difference becomes, as long as replication
remains single thread process. At the same time it is a lot easier to optimize your system when your replication runs normally - if you need to add/remove indexes and do other schema changes you probably would be looking at some methods involving replication if you can't take your system down. So here comes the catch in many systems - we find system is in need for optimization when replication can't catch up but yet optimization process we're going to use relays on replication being functional and being able to catch up quickly.

So the question becomes how can we estimate replication capacity, so we can deal with replication load before slave is unable to catch up.

Need to replication capacity is not only needed in case you're …

I started translation of Part 3 "Other cases". In this part I mostly describe how wrong settings can lead to misterious errors. First chapter in this part about large amount of data.

Part 3. Other cases.


Chapter 8. Large amount of data.

There are cases when query is just symptom of wrong behavior, but true reason is wrong settings.

One of the cases is too small max_allowed_packet for data sent. MySQL
server variable max_allowed_packet defines maximum possible amount of
data which MySQL server can receive or send. Amount of
max_allowed_packet is specified in bytes.

Error usually looks like:


$mysql51 test <phpconf2009_1.sql

ERROR 1153 (08S01) at line 33: Got a packet …

The closest thing I know of to a “Northern Virginia MySQL Meetup” is the Sterling Database Data Solutions Group. I got in touch with the organizer and we scheduled a meeting next Wednesday July 28th. I’ll be presenting, and so will someone from Fusion-IO, a solid-state storage vendor. This is on short notice, so tell your friends about it! It would be great to grow a strong monthly meetup presence in this area.

Yes, you read the title correctly — there are three editions of MySQL available, according to http://www.mysql.com/products/enterprise/server.html. Well, that page names two, and then of course there is the community edition….

From the manual page:

MySQL Enterprise Server is available in the following editions:

* MySQL Enterprise Server – Pro is the world’s most popular open source database that enables you to rapidly deliver high performance and scalable Online Transaction Processing (OLTP) applications.
* MySQL Enterprise Server – Advanced is the most comprehensive edition of MySQL. It provides all the benefits of MySQL Enterprise Server Pro and adds horizontal table and index partitioning for improving the performance and management of VLDBs (Very Large Databases).

How is “horizontal table …

At the beginning of a new project, one is faced with the question if MySQL's strict mode should be used or if the default behavior is sufficient for most scenarios. This mode certainly makes only sense if you evaluate the error codes and acting accordingly in the application - thus, it would be a bad idea to apply SQL modes to a running system. Unfortunately, SQL modes are not really common and have thereby a few bugs. Also the fact, that the user can bypass the mode in the session raises the question whether it makes sense to use these settings at all. I decided to only set a selected list of options; just what really makes sense and improve the behavior of MySQL. Strangely that these modes are not set by default, what one might expect, as they are close to a natural …

This is one of a few MySQL High Availability strategies.  I have used this for years and found it work great.  If you don’t know about DRBD and MySQL you should read Peter’s comments.

These are step by step instructions for Redhat 5 or CentOS.

If you need more details please refer to:
http://www.drbd.org/users-guide/

Configuring MySQL for DRBD
http://dev.mysql.com/doc/refman/5.1/en/ha-drbd-install-mysql.html

Getting started:

The OS in this example is CentOS 5.5.  I added a new disk (/dev/sde) to the four disk RAID-5 and RAID-1 I was already using.   I’m only creating an 8 …

For decades the debate between shared-disk and shared-nothing databases has raged. The shared-disk camp points to the laundry list of functional benefits such as improved data consistency, high-availability, scalability and elimination of partitioning/replication/promotion. The shared-nothing camp shoots back with superior performance and reduced costs. Both sides have a point.

First, let’s look at the performance issue. RAM (average access time of 200 nanoseconds) is considerably faster than disk (average access time of 12,000,000 nanoseconds). Let me put this 200:12,000,000 ratio into perspective. A task that takes a single minute in RAM would take 41 days in disk. So why do I bring this up?

Shared-Nothing: Since the shared-nothing database has sole ownership of its data—it doesn’t share the data with other nodes—it can operate in the machine’s local RAM, only writing infrequently to disk (flushing the data …