Insertion and Queries

Databases are complicated beasts, but I’d like to focus on the storage engine, just the part that talks to the storage system, and doesn’t have to worry about SQL, etc.: just transactions, concurrency, compression, updates and queries.  In the next couple of blog entry, I’d like to just focus on updates (insertions and deletions) and queries (point and range).  (This delineation between the
front end and the storage engine is clearly architected in MySQL.) And in particular, I’d like to explore which features of a disk limit performance for which operations.

The question is how fast can these operations go?  Point queries are the slow ones, so let’s start with them first.  Suppose you have data on a disk—say a 1TB Hitachi Deskstar 7K1000.  It has a disk seek time 14ms and transfer rate of around 69MB/s [See tomshardware.com] Now imagine filling the disk with a …

Alright so I thought I might throw my $0.02 into the whole fanfare about Sun acquiring MySQL. I think it was a surprising but good move. Sun has a lot to provide, is likely looking to strengthen their platform, and appears to be committed to open source. While it remains to be seen whether their promise of keeping MySQL relatively unchanged still needs to be proven, I tend to believe that they understand the value of MySQL (they certainly should given the price tag) and would not do anything to jeopardize that. MySQL is, after all, the world's most popular open source database (according to MySQL, but I think that is still true).

This move I think is good for MySQL as well (maybe even better). For one, it seems like it would protect them for a buyout by a competitor. Now realistically, if Oracle bought out MySQL, the GPL'd parts of it would be forked off quite quick and the remaining alienated users would likely move to PostgreSQL or …

Here are a few photos from our announcement in Orlando earlier this week.  It's been crazy busy, but the response has generally been very positive from our community, our customers and our employees. 

It's been fun to have some pretty cool Sun folks at our company meeting in Orlando including Rich Green, James Gosling, Ian Murdock, Bill Shannon, Karen Padir, Rich Lang, Dave Douglas, Eduardo Pelegrillo and others. (Also, thanks to Tobias for the photo of the long-haired guy playing RockBand at our party Wednesday night.) 

No doubt there will be a few gotchas here and there as we work out integration details, but I'm stoked.  Tired, but stoked. 

Still shell-shocked from the announcement of Sun's intent to acquire MySQL, I was among the many at Martin's presentation for whom his words seemed to miss our ears and whose eyes failed to register what was on the slides before us. A sea of silence. Martin quite nerviously continued on while, for me, I was stunned, expecting an IPO announcement and thinking that what was before me was a

is Jeb Miller. Not only does he manage to QA and break cluster (of course the whole point of QA) - this morning he brought in coffee. Marvellous. Brilliant. oh, and awesome.

A friend and I were talking about the relative valuations for open-source companies. Over on his blog, JBoss founder Marc Fleury had joked that, after seeing MySQL's valuation, he realized he clearly had "undersold."

But as it turns out, JBoss' valuation multiple was not much different from that of MySQL--which was snagged by Sun Microsystems this week for $1 billion.

The 451 Group is reporting MySQL's numbers as follows:

While MySQL has not disclosed revenue for 2007, it is believed that its revenue in 2006 was $34 million, up from $16 million in 2005 and $14 million in 2004. We estimate trailing 12-month (i.e., 2007) revenue to be about $48 million, and if we assume slightly slower growth in 2008, we get to about $65 million....Given that, it would …

Alright so I thought I might throw my $0.02 into the whole fanfare about Sun acquiring MySQL. I think it was a surprising but good move. Sun has a lot to provide, is likely looking to strengthen their platform, and appears to be committed to open source. While it remains to be seen whether their promise of keeping MySQL relatively unchanged still needs to be proven, I tend to believe that they understand the value of MySQL (they certainly should given the price tag) and would not do anything to jeopardize that. MySQL is, after all, the world's most popular open source database (according to MySQL, but I think that is still true).

This move I think is good for MySQL as well (maybe even better). For one, it seems like it would protect them for a buyout by a competitor. Now realistically, if Oracle bought out MySQL, the GPL'd parts of it would be forked off quite quick and the remaining alienated users would likely move to PostgreSQL or …

Read here how you can create them, how you can find them and what is the problem with them...

What is a sparse file?

"A sparse file is a file where space has been allocated but not actually filled with data. These space is not written to the file system. Instead, brief information about these empty regions is stored, which takes up much less disk space. These regions are only written to disk at their actual size when data is written to them. The file system transparently converts reads from empty sections into blocks filled with zero bytes at runtime." [1]

In other words: Files are not as big as expected.

With databases this can be seen often: For example the MySQL Cluster REDO log files are created as sparse files or some ORACLE tablespace files.

But first let us create such a sparse file:

 # dd if=/dev/zero of=sparsefile count=0 obs=1 seek=100G
 
 # ls -lah sparsefile
 -rw-r--r-- 1 oli users 100G 2007-10-24 11:18 sparsefile
 
 # df -h .
 Filesystem            Size  Used Avail Use% Mounted on …