On Friday I gave a presentation on “MySQL Query Patterns, Optimized” for Percona MySQL Webinars.  If you missed it, you can still register to view the recording and my slides.

Thanks to everyone who attended, and especially to folks who asked the great questions.  I answered as many as we had time for  during the session, but here are all the questions with my complete answers:

Q: Can you compare the use of subqueries/multiple joins vs. multiple queries (e.g. temp tables)?

For performance, it’s hard to make …

“Application designers need to start by thinking about what level of data integrity they need, rather than what they want, and then design their technology stack around that reality. Everyone would like a database that guarantees perfect availability, perfect consistency, instantaneous response times, and infinite throughput, but it´s not possible to create a product with [...]

Original images from Flickr user jenniferwilliams

One of our clients, for various historical reasons, runs both MySQL and PostgreSQL to support their website. Information for user login lives in one database, but their customer activity lives in the other. The eventual plan is to consolidate these databases, but thus far, other concerns have been more pressing. So when they needed a report combining user account information and customer activity, the involvement of two separate databases became a significant complicating factor.

In similar situations in the past, using earlier versions of PostgreSQL, we've written scripts to pull data from MySQL and dump it into PostgreSQL. This works well enough, but we've updated …

Last week Tokutek announced that they’re open-sourcing their TokuDB storage engine for MySQL. If you’re not familiar with TokuDB, it’s an ACID-compliant storage engine with a high-performance index technology known as fractal tree indexing. Fractal trees have a number of nice characteristics, but perhaps the most interesting is that they deliver consistently high performance under varying conditions, such as when data grows much larger than memory or is updated frequently. B-tree indexes tend to get fragmented over time, and exhibit a performance cliff when data doesn’t fit in memory anymore.

The MySQL community is excited about having access to TokuDB’s source code, and rightly so. TokuDB is, broadly speaking, aimed at the same category of use cases as Oracle’s InnoDB, …

Years ago I complained bitterly about MySQL’s backwards development and release model, which made guinea pigs out of the paying customers. I think I’d be remiss if I didn’t say it’s been fixed for years. And it’s really fixed right in my opinion — much better than what I proposed.

Congratulations, and thanks, to the MySQL team for superhuman software engineering, release engineering, documentation, bug triage and analysis, and doing a million things right — in other words, making a damn good database, which is hard. You know I still have gripes occasionally, and so do most people, but in the scheme of things — wow. MySQL is awesome.

We’re ironing out a kink that’s preventing Planet MySQL from aggregating VividCortex’s blog feed, so while that’s in progress, I’ll post a quick note on what we’re up to at VividCortex, for the Planet MySQL readers.

VividCortex is a monitoring and analysis product for MySQL, provided as Software-As-A-Service, with agents that run in your systems and report back to our APIs. The agents are super-efficient and non-obtrusive (you’ve probably noticed my posts about Go recently). They gather high-resolution data about your systems and our web application helps you make sense of it.

VividCortex is shockingly easy to install — if you’re slow at the keyboard, it takes 30 seconds. In less than a minute you can get insight into what your MySQL servers are doing. We are in closed beta right now, with a long waiting list. We’re working with a small set of alpha customers …

If you are importing large CSV or SQL dumps to MySQL, chances are you were looking for ways to see how far the import has gone. If you know how many rows there are from the file being imported, you can do a SELECT COUNT(*) but that would take sometime for the query to finish especially on really big imports.

Using lsof, you can monitor the current file offset to which a process is reading from using the -o option. Knowing the size of the file and some snapshots of the offset, you can get a somewhat rough idea of how fast the import goes. Note though that this is only file-read-pace not actual import speed as MySQL import can vary depending on a number of conditions i.e. table growth, secondary indexes, etc.

Let’s say I am importing a 1.1G CSV file into a table.

[revin@forge msb_5_5_300]$ ls -al /wok/dta/samples/ft_history.csv 
-rw-rw-r--. 1 revin revin 1075456654 Nov 8 23:25 /wok/dta/samples/ft_history.csv …

While I tried to deflect how you perform SQL Injection attacks against a MySQL procedure, my students requested that I post examples of what to do to avoid SQL injection, and what not to do to invite attacks. The best practice to avoid SQL injection attacks is too always bind inputs to data types, and avoid providing completely dynamic WHERE clauses.

Here’s the correct way to dynamically generate a result from a MySQL Stored Procedure:

CREATE PROCEDURE hello (IN pv_input VARCHAR(50))
BEGIN
  SELECT sample_id
  ,      sample_name
  FROM   sample
  WHERE  sample_name = pv_input;
END;
$$

A call to this hello procedure will only return the row or rows where the pv_input value matches the sample_name column value. Any attempt to exploit it like the one below fails.

CALL …

MySQL 5.6 through the eyes of a custom storage engine MySQL plugin

MySQL is famous for its pluggable storage engine architecture which allows a DBA or an application developer to choose the right engine for the task. An application uses MySQL API and is isolated from all of the low-level implementation details at the storage level. As an example, the Cloud Storage Engine (ClouSE) enables existing MySQL applications to use cloud storage such as Amazon S3 or Google Cloud Storage to store its data. The application doesn’t need to be changed or even redeployed: with ClouSE, remote cloud storage will look like a better (ultra-scalable, durable, always-on) alternative to the local storage.

As you may already know, ClouSE now supports MySQL 5.6 release …

I’m really looking forward to Percona Live this year. I will be there, along with Kyle Redinger, my co-founder at VividCortex. I feel that this year the conference has come full circle. 2007 was my first year at the conference, and it was amazing. This year is tremendously exciting for me because it feels like we’re back on the 2007 trajectory.

Those were the golden days. Things were a little sad in 2010 and 2011 as the MySQL community tried to figure out the new landscape and O’Reilly decided to stop running the event, but then in 2012 we all said “we’re back!” with the exception of Oracle, who instead arranged MySQL Connect, as part of Oracle Open World. I don’t think that was a huge success. I don’t know if that’s why Oracle has decided to participate in this year’s Percona MySQL conference, but frankly it …