It's frustrating seeing examples of MySQL being slow as an example of why you should use NoSQL. If you have an invested interest[1] in comparing two technologies that are already apples to oranges, the least you can do is optimize both. If you can't do it, don't share it.

This came out of a talk on Cassandra. "MySQL" is not on the slide, but it was mentioned in reference to MySQL:

SELECT * FROM tweets WHERE user_id IN (SELECT follower FROM followers WHERE user_id = ?) order by time_tweeted DESC LIMIT 40;

Let me simulate that for you:

CREATE TABLE `tweets` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_id` int(11) NOT NULL,
  `info` text,
  `time_tweeted` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  INDEX (time_tweeted),
  INDEX (user_id)
) …

There are a lot of weird things which MySQL does to handle its mix of transactional and non-transactional behaviour, but this one was new to me :)

create table t1 (ID INT NOT NULL PRIMARY KEY, V INT NOT NULL);

Query OK, 0 rows affected (0.01 sec)

mysql> insert into t1 (ID,V) VALUES (2,NULL);
ERROR 1048 (23000): Column 'V' cannot be null

mysql> insert into t1 (ID,V) VALUES (3,1),(4,1);
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

insert into t1 (ID,V) VALUES (5,1),(6,NULL);
Query OK, 2 rows affected, 1 warning (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 1

mysql> show warnings;
+---------+------+---------------------------+
| Level   | Code | Message                   |
+---------+------+---------------------------+
| Warning | 1048 | Column 'V' cannot be null | …

Over three years ago I wrote about how you cannot use a stored procedure in a subquery. Well, it’s 2010, and I’m still annoyed by this and a handful of other things.

I was just working today on a report consisting of a series of queries, taking about a minute to generate. Some of the data would be created in a temporary table and queried against multiple times for performance reasons, and ultimately spit out into a CSV file for someone to examine later. I also would like to be able to return the result set, and perform queries on it, which is much faster than querying a view.

Fortunately, MySQL’s awesome SELECT … INTO OUTFILE can easily write CSV files to disk, so I’m covered there.

So when I …

Dear interweb, if you have no idea what you’re writing about, keep it to yourself, don’t litter into the tubes. Some people may not notice they’re eating absolute crap and get diarrhea.

This particular benchmark has two favorite parts, that go with each other together really well:

I didnt change absolutely any parameters for the servers, eg didn’t change the innodb_buffer_pool_size or key_buffer_size.

And..

If you need speed just to fetch a data for a given combination or key, Redis is a solution that you need to look at. MySQL can no way compare to Redis and Memcache. …

Seriously, how does one repay for all the damage of such idiotic benchmarks?

P.S. I’ve ranted at benchmarks before, and will …

Over the last 5 years, I’ve read so many articles about how X doesn’t scale. PHP, MySQL, SQL Server, Apache, you name it – everything gets a bad rap. Everyone has a different idea of scale and size, and sadly most people think their site with 1 million page views a month can’t handle the load because whatever technology they chose to use supposedly doesn’t scale.

Guess what folks – the problem probably isn’t the language you chose, or the database you’re using. Unless you’re actually big (many millions of pageviews per day), you can usually run just fine with a straight up LAMP stack on a few servers. The real issue is that your dev team has no idea how to write software or use the tools they have available.

At this point, I wonder – what is everyone’s expectation? At what point does someone say “oh, X scales great! One box is handling my web server, data storage, video conversion, at 20 million page views a …

So we've been there.

In my opinion the conference was a great success. Our presentation was not, but that's another story. Percona really showed what conferencing is about. Don't know about MySQL. It was behind the closed doors. Valiant guardians strictly watched that you didn't overhear a word of Sacred Knowledge. Hell, even to get to the Expo hall you had to pay $25 (that's right, you had to pay for watching advertisement) and surrender information about your private life, like your phone number and how you learned about the Expo.

read more

Ummmmmfff…. wind out of my sails today. I believe their was an analyst who predicted this a year ago when Sun bought MySQL…. I wish I could find the article. I am going to head down to the UC floor and get a feel for what people are thinking… will post more as I get time.

Heavy testing, headphones with no music, lots of Sanchez Gran Reserva, headphones with Miles Davis, more testing, an updated Installation Guide, Charles Mingus & Eric Dolphy, and I still couldn’t get a Release Candidate out.

Well, such is the life of the multi purpose hacker. Other people are always finding out new purposes for you, which makes your free time aproach zero.

Does this mean that the release date of rc-1 will never come? Nah, I don’t think so. I have high hopes for the next iteration.

Wanna help me? Please test the installation guide, and then test the cluster itself. There’s a contact mail in the guide (yep, I don’t fear spam, I love it, it’s great for art).

Thanks to the 5000+ anonymous folks …

I scrubbed the SQL here to protect the innocent, but check this fun stuff out.  Working with a client who randomly started seeing huge spikes in CPU and disk activity on their server after weeks of seemingly running fine.  I tracked it down to a subset of long running queries.  These queries typically run in around a second per run, but out of the blue they started taking 600 seconds.

Here is the explain for the first query:

Explain:

Boy am I sick or what, maybe I should see a shrink or something.  What’s the first thing that runs through my head when I wake up on a Sunday morning?  Is it thoughts of family, the days events, happy thoughts or something pleasant non technical?  No.  Its that we need a better benchmark suite for MySQL and the open source database community as a whole.  Right now the staple of our benchmarking diet is sysbench and dbt2.  While both have served their purpose they are a bit long in the tooth and do not do a good job of truly capturing what end users are doing out their.  I mean sysbench uses a single table!   Where’s the join love.  Has anyone outside of a PT expert successfuly gotten dbt2 installed?  probably not because its a pain in the rear.   Plus what the hell does box A got a TPM of 5000 vs box B’s TPM of 6000 mean?  Seriously to a client the only thing it tells is in …