Posts Categorized: Technical Blog

Replication is the New Durability (Thoughts About Dynamo)

Dynamo: Amazon’s Highly Available Key-value Store” is a high level description of a data store, written by Amazon to solve the problem of a system where updates must never ever fail and must take less than a specific amount of time in 99.99% of the cases. No matter what happens to the servers or the network, updates to the system must continue as usual, and they emphasize that they deal with hardware and network failures nearly constantly.

A grand tour of Oracle Exadata, Part 2

After covering hardware components of Sun Oracle Database Machine in part 1, our grand tour continues with a look at the software side. With the prominent exceptions of the Exadata storage server software and the Oracle database itself, the software stack is based on well-known and widely used open source products.

Webinar: What you need to know for a MySQL 5.0 -> 5.1 upgrade

IOUG has a free series of three webinars on upgrading MySQL. Each webinar is an hour long, and it starts with a webinar by me tomorrow at 12 noon Central time (GMT-5) on “Why and How to Upgrade to MySQL 5.1″. The webinar assumes you are upgrading from MySQL 5.0 to MySQL 5.1, and talks a little bit about the new features, server variables, and what you need to know when upgrading to MySQL 5.1.

Using MySQL Partitioning Instead of MERGE Tables

One common question I get is how to use partitioning instead of MERGE tables. The process I use involves using stored procedures to create and drop partitions. This article will go over the stored procedures I use; special thanks to Roland Bouman for taking a look and giving great feedback to optimize this process.

Meddling with Test::Builder (helloooo Test::Wrapper)

Following up on my threat of last week, I released Test::Wrapper on CPAN. If you read my previous blog entry, you know that one of the big gotchas of the wrapping gymnastics I was doing was that it was utterly #@$%$# up Test::Builder’s internal states. Thus, at that point, it was either run TAP tests, or use Test::Wrapper, but don’t do both at the same time. Not the most God-awful limitation ever, perhaps, but still not very cool. Since then, I’ve taken a second look at the problem, and realized that this limitation can not only be overcome, but in a surprisingly easy manner.

Building a SQL Server Failover Cluster on Windows Server ’08 Pt 1

As I’ve already gone thru building a Windows Server 2008 cluster in this blog post, let’s have a look at installing SQL Server 2008. Whether you’re looking at R2 or non-R2 versions of both Windows Server 2008 and SQL Server 2008, the steps are almost the same except for some PowerShell support for Windows Server 2008 on the Clustering side and whether or not you’re dealing with Hyper-V LiveMigration as part of your cluster (this, however is beyond the scope of this blog post).

Three Editions of MySQL are Available

Those of us that have been around for the past 3 or so years know that there was a point in time where there were two different editions of MySQL available, back when MySQL Enterprise and MySQL Community were actually different. But that experiment was a complete failure, and the code is now the same. MySQL Enterprise does package the software in a way that is not available to the community, specifically the quarterly service pack (QSP) releases. But the actual code….the same.

Exadata’s Best Kept Secret: Storage Indexes

Although many electrons have been expended discussing Exadata’s features, storage indexes tend to figure last, with a vague mention of row elimination in heavily clustered data. Even Oracle’s Exadata software user guide devotes barely half a page to them. Unlike the better known smart scanning features though, storage indexes have an important advantage: rather than offloading workload to storage cells, they eliminate the need to do the I/O at all. Here are some sample statistics taken from an actual production system:

Environment Variables in Grid Control User Defined Metrics

Emerson wrote: “Foolish consistency is the hobgoblin of small minds”. I love this quote, because it allows me to announce a presentation titled “7 Sins of Concurrency” and then show up with only 5. There are places where consistency is indeed foolish, while other times I wish for more consistency. Here is a nice story that illustrates both types of consistency, or lack of.

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