This is the first of two articles on sampling queries effectively. The second part is here.

Sampling is hard. This is the title of a talk I gave at a meetup in Boston a few weeks back. But what’s so hard about sampling anyway?

To begin with, let’s clarify what I mean by sampling. It’s a bit ambiguous because sampling could apply to a few different things one does with time series data. In this context, I’ll be talking about capturing individual events from a large, diverse set of events (queries).

Here’s a picture of a simple stream of events over time.

Notice that they are not all the same–some of them are higher or lower than others. This is a simple illustration of some variability in the stream.

The way VividCortex generates query insight is by computing metrics about the …

In the MySQL team we are currently discussing if we should deprecate the integer display width in numeric types. For example:

CREATE TABLE my_table (
 id INT(11) NOT NULL PRIMARY KEY auto_increment
);

The (11) does not affect the storage size of the data type, which for an INT will always be 4 bytes. It affects the display width.
Our rationale for proposing this should be deprecated is that it is a common source of confusion amongst users.

We are …

Percona is glad to announce the release of Percona Server 5.5.44-37.3 on July 1, 2015. Based on MySQL 5.5.44, including all the bug fixes in it, Percona Server 5.5.44-37.3 is now the current stable release in the 5.5 series.

Percona Server is open-source and free. Details of the release can be found in the 5.5.44-37.3 milestone on Launchpad. Downloads are available …

Percona is glad to announce the release of Percona Server 5.6.25-73.0 on July 1, 2015. Download the latest version from the Percona web site or from the Percona Software Repositories.

Based on MySQL 5.6.25, including all the bug fixes in it, Percona Server 5.6.25-73.0 is the current GA release in the Percona Server 5.6 series. Percona Server is open-source and free – and …

Wed, 2015-07-01 12:54anderskarlsson

It was a very long time since I wrote something in this blob, but I have been very busy this spring with MariaDB on Power. This has been a lot of work, but also a lot of fun. So, what is this MariaDB on Power thing all about, well I wrote an introduction to the Power platform late last year. Since then a lot of things has happened.

One thing is that several service providers out there have adopted Power8 as a platform. To be honest, this really isn't sexy, but it is useful and as a user of one of these services, you will just see the same old Linux you are used to, but potentially it is more powerful and reliable. One such provider is OVH, whose service is more known as RunAbove. If you want to try it, you can do so for …

Quite often, especially for benchmarks, I am trying to limit available memory for a database server (usually for MySQL, but recently for MongoDB also). This is usually needed to test database performance in scenarios with different memory limits. I have physical servers with the usually high amount of memory (128GB or more), but I am interested to see how a database server will perform, say if only 16GB of memory is available.

And while InnoDB usually respects the setting of innodb_buffer_pool_size in O_DIRECT mode (OS cache is not being used in this case), more engines (TokuDB for MySQL, MMAP, WiredTiger, RocksDB for MongoDB) usually get benefits from OS cache, and Linux kernel by default is generous enough to allocate as much memory as available. There I should note that while TokuDB (and TokuMX for MongoDB) supports DIRECT mode (that is bypass OS cache), we found there is a performance gain if OS cache is used for compressed pages.

It’s important to monitor the (database) backups after you set-it-up. In this post we will answer a few how to monitor MySQL Database backups solutions – monitoring methods. We should…

The post How to monitor MySQL backups first appeared on Change Is Inevitable.

I used Ubuntu 12.04 LTS on Amazon EC2 to download, compile, and install Varnish cache.

As of this writing, you can find the latest stable release at https://www.varnish-cache.org/releases

One of the decisions I notice acutely about other companies’ products is their user model. I always notice it, and it makes me either smile or grit my teeth. Companies get this wrong all the time.

• Right: a user account owns itself and is affiliated to a company/organization/etc. It may belong to teams and have various levels of permissions. But the person who created the account owns the account.
• Wrong: a user account is created and owned by, and depends on, an organization or company.

The difference may seem silly. Why would anyone care?

Think of GitHub. You probably have your own opensource repos, and you probably participate in your company’s repos. You probably also participate in some teams for repos that you care about, which are owned by other organizations or users. You can do this all with a single account.

What if …

We recently added a token-based authentication example to the Siesta repository that provides an excellent starting point for building authenticated APIs using our lightweight HTTP handler library for Go. This example, modeled after our own internal API services, demonstrates features and practices that we’ve developed and found useful after using Siesta in production for many months.

Here’s what you’ll see in this “meaty” example:

• Request identification and logging
• Token-based authentication
• Use of typed URL parameters
• Usage of a handler for some state, such as a database
• JSON responses
• “Pre” and “post” middleware chains
• Error handling and bypassing of handlers …