Teradata Q1 disappoints. Actian acquires ParAccel. And more.

For 451 Research clients: Acquisitive Actian adds ParAccel to its growing database portfolio bit.ly/YgeY7k

— Matt Aslett (@maslett) April 29, 2013

For 451 Research clients: Tokutek releases TokuDB database storage engine as open source bit.ly/102xsSW

— Matt Aslett (@maslett) May 1, 2013

For 451 Research clients: Codership replicates partnership success with Galera Cluster for MySQL bit.ly/15dI8Hh

— Matt Aslett (@maslett)

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This afternoon, Arjen Lentz and I were discussing InnoDB’s behavior without a declared PRIMARY KEY, and the topic felt interesting enough and undocumented enough to warrant its own short post.

Background on InnoDB clustered keys

In The physical structure of InnoDB index pages I described how “Everything is an index in InnoDB”. This means that InnoDB must always have a “cluster key” for each table, which is normally the PRIMARY KEY. The manual has this to say in Clustered and Secondary Indexes:

If the table has no PRIMARY KEY or suitable UNIQUE index, InnoDB internally generates a hidden clustered

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A cold cache, or a poorly tuned cache can be responsible for a number of performance problems. If we look at the data and indexes of InnoDB, the cache responsible is called the InnoDB buffer pool.

In earlier versions of MySQL the default value for the setting innodb_buffer_pool_size was 8M - which is a little out of date when you consider the recommended value to be 50-80% of system memory. In MySQL 5.5 the default value was increased to 128M, which is a comprimise made for users that may install MySQL on a development machine and not have it running as a dedicated server. In production, it is unlikely that you will buy a new server with less than 64GB of RAM, so it is quite typical that this setting is 50GB+

So lets talk about the behavior of the InnoDB buffer pool -

Up until and including MySQL 5.5

When MySQL

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SAP HANA , having entered the data 2.0/3.0 space at the right time, has been getting traction lately; and there will be lot of users like me who wants to[...]

Normal 0 false false false EN-US X-NONE X-NONE Everybody loves free. It is the best marketing term one could use. Once you say “FREE” the people come running. Free makes you very popular. Whether you are a politician offering something for free, or a company providing free stuff, you gain instant popularity.

Xeround is shutting down their MySQL Database as a Service (DBaaS) because their free


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Sharing my experience of compiling TokuDB + MariaDB 5.5. Why? Because I must have this patch to Sphinx 2.0.4.

Note: I was using what seems to be the "old" method of compiling; quoting Leif Walsh:

... We are looking at deprecating that method of building (MariaDB source plus binary fractal tree handlerton).  It only really needed to be that complex when we were closed source.

I also tried the "new" method of compiling, which I couldn't work out.

Here's how it goes: TokuDB is newly released as open source. As such, it got a lot of attention, many downloads and I hope it will succeed.

However as stable as the

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A friend wrote to me recently with a question. He was working on a method to ship application metrics to statsd on a 1 minute interval. He had three examples of how to estimate the number of rows in a table and he wanted to know the difference between them.

Data length/average row length

The example given:

mysql> select DATA_LENGTH/AVG_ROW_LENGTH from INFORMATION_SCHEMA.TABLES where
 TABLE_NAME = 'line_items';
+----------------------------+
| DATA_LENGTH/AVG_ROW_LENGTH |
+----------------------------+
|              10497541.7528 |
+----------------------------+
1 row in set (0.03 sec)

I have actually never thought of using this method! I don’t think it’s accurate though, since data length has deleted space +

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I find a good interview question for a MySQL DBA position is to ask what the following commands actually do in InnoDB, which has been the default storage engine since MySQL 5.5. From my perspective there is a lot of miss-understanding what still applies.

ANALYZE TABLE

From the MySQL manual:

ANALYZE TABLE analyzes and stores the key distribution for a table. During the analysis, the table is locked with a read lock for InnoDB and MyISAM.

What this means is, as part of query optimization MySQL will often have to decide which is the best index if there are multiple candidates, which indexes should be avoided, and what order should tables be joined in. Indexes need to eliminate work - so if for example you were trying to index a column

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I’ve put online the slides for the two talks that I сo-presented at the Percona Live conference:

• Advanced query optimizer tuning and analysis tutorial (slideshare, pdf)
• MariaDB Cassandra interoperability session (slideshare, pdf)

The tutorial tries to cover most areas of the optimizer, with focus

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Got a packet bigger than ‘slave_max_allowed_packet’ bytes and binlog_format=STATEMENT|MIXED

Since version 5.1.64 MySQL introduces a new variable named slave_max_allowed_packet, which was introduced to allow large updates using row-based replication do not cause replication to fail when exceeded max_allowed_packet.

The problem is if you have you replication using binlog_format=STATEMENT or binlog_format=MIXED it ignores this option and use as limit for queries what is on max_allowed_packet variable but still reporting on slave_max_allowed_packet

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5 years of MySQL

People often write a blog post when they reach some nice anniversary since they joined MySQL community. Well, for those old enough it usually means when they joined MySQL AB as employee. For me this was January 2008. Because I didn't remember the month correctly, I haven't blogged anything then, but decided to save it for a better opportunity - now.

TL;DR Starting this week I will be working for 10gen, selling MongoDB to the Nordics. This blog post is really long - even then it doesn't contain the most interesting stories, I'm not sure if they can ever be published. Sorry for the length, but remember you don't need to read all at once. This is my last MySQL post so save some of it for cold winter days!

2008 - Sun acquisition

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Hey everybody!

The Percona Live MySQL Conference and Expo just wrapped up last week and we’re looking to get some conference in review talk from everyone! Talk about your favorite sessions, new things you learned, and your overall opinion of the conference!

Hop online Wednesday at 12:00pm PDT (19:00 GMT) to join the discussion and share your experience from the 2013 Percona Live: MySQL Conference and Expo.

Be sure to watch this twitter search or this blog post get a link for the google hangout tomorrow!

Some talks that were specifically called out:

• Monitoring MySQL with OpenTSDB by Geoffrey Anderson

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I wasn’t at the MySQL Conference this year but it was very nice to follow this event from Paris.
Of course I didn’t feel the general atmosphere by visiting booths or met fabulous people.
But it was a great opportunity to offer you a live post about the conference with an external point of view.

Twitter, RSS feeds (yes Google, I still use RSS), Planet MySQL and infiltrators were my best friends during this crazy week.

I would like to summarize the major announcements and events occurs during this tenth edition.
 

Oracle at Percona Live!

 
Yes, Oracle was at Percona Live 2013 and it was for the best.
I invite you to watch this

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As you may know, I'm a big fan of JSON and I am working on releasing a new version of my JSON tools real soon. Meanwhile on the SkySQL Solutions Day on April 26 I gave a talk on JSON with MySQL and MariaDB, and the slides are available on slideshare.

/Karlsson