In writing a recommendation for our Web development team on how to use MySQL, I came up with the following list, which I want to share: What kind of queries are bad for MySQL?

• Any query is bad. Send a query only if you must. (Hint: use caching like memcache or redis)
• Queries that examine many rows are bad. Try instead to use…
  

      SELECT col1 FROM table1 WHERE primary_key_column=SOMETHING

  
  . Or at least
  

  secondary_key_column=SOMETHING

  
  . If it is still not possible, try to make the query examine the least amount of rows possible (zero is ideal, as we come to the first case here)
• Queries with JOINS are bad. Try to denormalize the table to avoid JOINS. Example: original query
  

      SELECT t2.value FROM t2 JOIN t1 ON (t1.id=t2.tid) WHERE t1.orderdate=NOW()

  
  . This can be denormalized by copying the column orderdate from table …

I am actually quite excited about Tokutek’s release of TokuMX. I think it is going to change the landscape of database systems and it is finally something that made me looking into NoSQL.

Why is TokuMX interesting? A few reasons:

• It comes with transactions, and all that good stuff that transactions provide: a concurrent access to documents (no more global write-lock in MongoDB); crash recovery; atomicity
• Performance in IO-bound operations
• A good compression rate, which is a money-saver if you use SSD/Flash
• But it is also SSD/Flash life-time friendly, which is double money-saver

So having all these factors it is just a no-brainer if you have a …

We’re less than a week away from Percona MySQL University at Portland, Oregon next Monday, June 17. The latest in a series of FREE one-day educational events, we are pleased to feature 10 technical talks by members of Team Percona as well as local members of the MySQL Community:

• Vadim Tkachenko, Percona co-Founder and CTO, will talk about Percona XtraDB Cluster, …

I was reviewing the Percona Live sponsors list the other day and pondering the potential success stories associated with this product or that one…. and as I was preparing to put more thought on the topic, a PlanetMySQL post caught my eye. It was penned by Mike Hogan and titled, “Thoughts on Xeround and Free!”

For some reason the author of that post makes a connection between a free account in a cloud-based service and Open Source software. I think it’s an incorrect analogy, as they are two totally different things. A “free account” in this case is really just a marketing tool. Well, I admit there are companies that also use the “Open …

The Micron P320h SSD is an SLC-based PCIe solid-state storage device which claims to provide the highest read throughput of any server-grade SSD, and at Micron’s request, I recently took some time to put the card through its paces, and the numbers are indeed quite impressive.

For reference, the benchmarks for this device were performed primarily on a Dell R720 with 192GB of RAM and two Xeon E5-2660 processors that yield a total of 32 virtual cores. This is the same machine which was used in my previous benchmark run. A small handful of additional tests were also performed using the Cisco UCS C250. The operating system in use was CentOS 6.3, and for the sysbench fileIO tests, the EXT4 filesystem was used. The card itself is the 700GB model.

So let’s take a look at the data.

With the sysbench fileIO test in asynchronous …

I actually don’t remember exactly whether it was in 2006, 2007 or 2008 — but around that time the MySQL community had one of the greatest MySQL conferences put on by O’Reilly and MySQL. It was a good, stable, predictable time.

Shortly thereafter, the MySQL world saw acquisitions, forks, times of uncertainly, more acquisitions, more forks, rumors (“Oracle is going to kill MySQL and the whole Internet”) and just a lot of drama and politics.

And now, after all this time some 6 or 7 years later, it feels like a MySQL Renaissance. All of the major MySQL players are coming to the Percona Live MySQL Conference and Expo 2013. I am happy to see Oracle’s engineers coming with talks — and now with a great MySQL 5.6 release — and I have great …

For this post I’m going to shamelessly exploit the litany of technical problems SimCity players encountered earlier this month and a few examples of how Thread Pool for MySQL and Percona Server for MySQL can help to prevent such incidents.

Users of SimCity, a city-building and urban planning simulation video game, encountered network outages, issues with saving progress and problems connecting to the game’s servers following a new release a couple of weeks ago featuring a new engine allowing for more detailed simulation than previous games. During this same time, we happened to be testing the Thread Pool feature in Percona Server for MySQL, and I saw a connection of how Thread Pool is supposed to help in such cases.

Basically SimCity users faced the same situation …

Accessing Percona XtraDB Cluster nodes in parallel with MySQL asynchronous calls

This post is followup to Peter’s recent post, “Investigating MySQL Replication Latency in Percona XtraDB Cluster,” in which a question was raised as to whether we can measure latency to all nodes at the same time. It is an interesting question: If we have N nodes, can we send queries to nodes to be executed in parallel?

To answer it, I decided to try a new asynchronous call to send a query to MySQL using a new MySQLnd driver for PHP. In this post I’ll only show how to make these calls, and in following posts how to measure latency to all nodes.

PHP does not provide …

Percona Server on the Nexus 7: Your own MySQL Database Server on an Android Tablet

Following Roel’s post, Percona Server on the Raspberry Pi: Your own MySQL Database Server , I thought what other crazy gadget can I run Percona Server on? And having an Asus Nexus 7 Android tablet I decided to give it a try.

Anything below contains a risk that you break your tablet if you do not know what you are doing, so be advised.

First, we need rooted tablet, most likely with custom ROM. I personally use …

InnoDB’s checkpoint algorithm is not well documented. It is too complex to explain in even a long blog post, because to understand checkpoints, you need to understand a lot of other things that InnoDB does. I hope that explaining how InnoDB does checkpoints in high-level terms, with simplifications, will be helpful. A lot of the simplifications are because I do not want to explain the complexities of how the simple rules can be tweaked for optimization purposes, while not violating the ACID guarantees they enforce.

A bit of background: Gray and Reuter’s classic text on transaction processing introduced two types of checkpoints beginning on page 605. There is a sharp checkpoint, and there is a fuzzy checkpoint.

A sharp checkpoint is accomplished by flushing all modified pages for committed transactions to disk, and …