The latest from the MySQL community

When it comes to the query tuning, EXPLAIN is one the most important tool in the DBA’s arsenal. Why is a given query slow, what does the execution plan look like, how will JOINs be processed, is the query using the correct indexes, or is it creating a temporary table? In this blog post, we’ll look at the EXPLAIN command and see how it can help us answer these questions.

This is the thirteenth installment in the ‘Become a MySQL DBA’ blog series. Our previous posts in the DBA series include Database Indexing, Deep Dive pt-query-digest, Analyzing SQL …

Recently, I had a requirement to update my script console output depending on user key-press. Since calculation was done by background threads, I also wanted to prevent CTRL+C from stopping the script without proper cleanup.
However, looks like seamless handling of key-press along with handling special sequences is not available in Powershell. This was to be expected given that [system.console]::readkey is designed for accepting the user input which is mostly answers to flow control questions. Register-EngineEvent does not help either.

Anyway, let's tackle both problems one by one:
1) Disable CTRL+C from stopping the script:

            [console]::TreatControlCAsInput = $true

Note that CTRL+BREAK will end the session entirely and do the …

In my first Blog ever, I am going to cover the migration of a SQLite-Database to MySQL. The Tool used is MySQL-Workbench, which you can Download from the MySQL website. In this particular case, it is about the upgrade of mocenter 0.2 to 0.3.

In the Workbench on the right side, you have the button “Database Migration”. Once you click on it, the introduction to the migration wizard will show up.

Setting up source and target

On the bottom of the screen there is a button called “Start Migration”. Click it to get to the source selection.

On the first drop down menu choose “SQLite”. The menu will now change and give you the possibility to load a file. After you did this you …

Mon, 2015-10-19 07:19geoff_montee_g

My last row-level security blog post got a few questions, so I decided that it would be good to follow up with more detail. The last blog post described some basic information about row-level security, but row-level security policies are highly dependent on an application's or organization's security requirements. In this blog post, I'm going to walk through an example row-level security implementation in MariaDB 10.0 in a little more detail.

In this blog post, I'll do the following:

1. Describe a fictional application.
2. Outline a set of row-level security requirements for the application.
3. Show how to meet the security requirements by securing the relevant parts of the application's schema.

The Application

In this example, my fictional …

It’s our pleasure to announce that VividCortex now fully supports Amazon Web Services’ Aurora, a new and exciting evolution in database technology. As a fresh and high-powered alternative to MySQL, Oracle, Microsoft SQL Server, and PostgreSQL, Aurora is sure to make waves in database services worldwide.

According to AWS, “Aurora is designed to offer greater than 99.99% availability, replicating 6 copies of data across 3 Availability Zones and backing up data continuously to Amazon S3.” It’s highly scalable too: “You can use Amazon RDS to scale your Amazon Aurora database instance up to 32 vCPUs and 244GiB Memory.You can also add up to 15 Amazon Aurora Replicas across three availability zones to further scale read capacity. Amazon Aurora automatically grows storage as needed, from 10GB up to 64TB.”

Aurora has been the focus of database aficionados all …

MariaDB 10.1 not only contains tons of new features, it has also been polished to deliver top performance. The biggest improvement has been achieved for scalability on massively multithreaded hardware.

The following numbers show the throughput for a simplified sysbench OLTP benchmark on MariaDB-10.1.8 compared to MariaDB-10.0.21:

With the release of 10.1.8, MariaDB takes a next step. MariaDB 10.1 is now considered a stable release.

MariaDB 10.1 has a couple of main themes:

• Security
• High Availability
• Scalability

During the last few years there have been many request for more security features in MariaDB. Actually it’s a trend in general. Since open source software is getting more attractive all the time, more functionality is wanted in areas where proprietary software typically has been leading. This is especially true for databases. In addition data privacy is a very hot topic.

The big new thing in security for MariaDB 10.1 is a complete data at rest encryption solution. The encryption that now is in use originates from Google’s encryption patch. It has now been migrated into MariaDB 10.1. The …

A common way to implement point in time recovery capability is:

to regularly do a full backup of a database, and to save the binary logs of that database (or from its master if doing backups on a slave).

When point in time recovery is required you need to:

restore a backup, and apply the binary logs up to the point of recovery.

(Step # 2 and # b above are the ones that will be simplified

A while ago I wrote a blog post about time series database requirements that has been amazingly popular. Somewhere close to a dozen companies have told me they’ve built custom in-house time series databases, and that blog post was the first draft of a design document for it.

One of the things I said in the post was that I had no use for the “tagging” functionality I’ve seen in time series databases such as OpenTSDB. I’ve since reconsidered, although I think the functionality I now want is a bit different.

What does it mean to “tag” metrics? Typically, many time series databases let you add name=value pairs (tags) to individual time series points (observations). For example, you measure CPU usage to be 59% at 3:41PM on host inst413, and you tag this measurement as “shard=81” because inst413 holds data for shard 81. …

Recently I blogged about identifying necessary index changes when changing the character set for a MySQL database. In this follow-up post I want to talk about general schema changes that you should consider when changing your character set from latin1 to utf8, from utf8 to utf8mb4, etc. The main issue is with long VARCHAR columns and columns with columns with length limits that are enforeced in bytes rather than characters.

The manual points out the main areas where you may have trouble:

• A TINYTEXT column can hold up to 255 bytes, so it can hold up to 85 3-byte or 63 4-byte characters. Suppose that you have a TINYTEXT column that uses utf8 but must be able to …