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Displaying posts with tag: Databases (reset)
Pentaho changes

I’m back at my favorite spot at the Orlando airport:

This week has gone bye so fast it’s kinda scary.  I got dragged into one meeting after another design session after another knowledge transfer opportunity for 5 days in a row.  After our long working days, the discussions and talks just continued over dinner and beers.

It was great to meet everyone and as always we had a good time around the office and at the Ale House.  I even managed to stay sober this time around.  Well at least most of the time.

As always, the thing that struck me the most was how fast Pentaho changes.  It’s almost like visiting a different company every time I drop in.  Since I don’t see the day-to-day changes around the office, the difference between the first time I visited (15 people) and now (70+) is striking.  The office space occupied more than doubled for example.

Well, let me tell you, …

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When (n) counts?

I have seen on many engagements the column data type is defined as INT(1).

People have the misconception that this numeric integer data type is of the length of one digit, or one byte. (One digit is 0-9 an one byte is 0-255)

This is incorrect.

Integer

For integer numeric data types in MySQL, that is TINYINT, SMALLINT, MEDIUMINT, INT, BIGINT the (n) has no bearing on the size of data stored within the specific data type. The (n) is simply for display formatting.

In the MySQL Manual 10.2. Numeric Types you read This optional display width is used to display integer values having a width less than the width specified for the column by left-padding them with spaces. The display width does not constrain the range of values that can be stored in the column, nor the number of digits that are displayed for values …

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The minimum testing for a shared disk MySQL environment

Recently I was asked to provide guidelines for testing fail over of a MySQL configuration that was provided by a hosting provider.

The first observation was the client didn’t have any technical details from the hosting provider of what the moving parts were, and also didn’t have any confirmation other then I think a verbal confirmation that it had been testing.

The first rule in using hosting, never assume. Too many times I’ve seen details from a client stating for example H/W configuration, only to audit and find out otherwise. RAID is a big one, and is generally far more complex to determine. Even for companies with internal systems I’ve seen the most simple question go unanswered. Q: How do you know your RAID is fully operational? A: Somebody will tell us? It’s really amazing to investigate on site with the client to find that RAID system is running in a degraded mode due to a disk failure and nobody knew.

It …

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Fwd: Scorching hot Startup Needs Scalability Sorcerer and Optimization Freak

Question: Do you think you have what it takes to take a service from a few hundred thousand users to tens of millions of users in 1 year flat? If you do read on and perhaps become the next beloved scalability rockstar of our age.

We are looking for a data charmer. A mysql magician. A code hack. A funny man. A mad man. A passionate man. Or perhaps a woman who does all these things and more.

Here’s what you gotta do:

  • Pro-active and reactive performance analysis, monitoring and general database plumbing of all leaky issues.
  • Work with others on the team to help maintain/improve and support the infrastructure for a high traffic, high growth site
  • Optimize and tune the database day to day
  • Algorithmic bent. Develop algos to quicken search times, response times, find shortest paths between various connections on site.
  • Have solid low level …
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BIGINT v INT. Is there a big deal?

The answer is yes.

In this face off we have two numeric MySQL data types, both Integer. In fact MySQL has 9 different numeric data types for integer, fixed precision and floating point numbers, however we are just going to focus on two, BIGINT and INT. This design consideration is part of my recent presentation Top 20 Design Tips for Data Architects.

What is the difference?
We turn to the MySQL Reference Manual first, in 10.1.1. Overview of Numeric Types we see the following.


INT[(M)] [UNSIGNED] [ZEROFILL]

A normal-size integer. The signed range is -2147483648 to 2147483647. The unsigned range is 0 to 4294967295.

BIGINT[(M)] [UNSIGNED] [ZEROFILL]

A large integer. The signed range is …

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Ivan Needs Your Help

Please help save Ivan, son of Andrii Nikitin (MySQL Support Engineer), who needs a bone marrow transplant. Andrii’s message is below:

“My family got bad news - doctors said allogenic bone marrow transplantation is the only chance for my son Ivan.

“8 months of heavy and expensive immune suppression brought some positive results so we hoped that recovering is just question of time.

“Ivan is very brave boy - not every human meets so much suffering during whole life, like Ivan already met in his 2,5 years. But long road is still in front of us to get full recover - we are ready to come it through.

“Ukrainian clinics have no technical possibility to do such complex operation, so we need 150-250K EUR for Israel or European or US clinic. The final decision will be made considering amount we able to find. Perhaps my family is able to get …

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How to Truncate All or Some of the Tables in a MySQL Database

Truncating all tables in a database is a common problem which arises a lot during testing or debugging.
One of the most common answers to this question is to drop & recreate the database, most likely utilizing the shell. For example, something like this:

mysqldump --add-drop-table --no-data [dbname] | mysql [dbname]

This dumps the entire schema structure to disk, without dumping any data, and with commands for dropping existing tables. When loading it back into mysql, it essentially truncates all the tables in the database. Basically, this is a decent solution for many uses.

We had a requirement for a solution that needed these additional features:

  1. Does not require shell (We work with both Linux and Windows)
  2. Resides inside the MySQL Server (To minimize outside dependencies - for example - the mysql command line client)
  3. Can truncate only specified tables using a …
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Delivering The Goods

Mysql Connector/J (5.1.5, JDBC Driver) is delivered to the OpenSolaris source as part of the Webstack project, and should show up in build 92. The JDBC driver will be located at

/usr/mysql/connectors/jdbc/5.1

So check out OpenSolaris at build 92 ;)

Delivering The Goods

Mysql Connector/J (5.1.5, JDBC Driver) is delivered to the OpenSolaris source as part of the Webstack project, and should show up in build 92. The JDBC driver will be located at

/usr/mysql/connectors/jdbc/5.1

So check out OpenSolaris at build 92 ;)

Pondering MapReduce

I spent this past weekend writing a Paper for a project I’ve been playing with. It is a simplified distributed processing system loosely based on Google’s MapReduce, except rather than focusing on larger batch jobs, it prototypes out some common database application uses. The model is currently very basic, but I plan on exploring this further (possibly with a performance-enhanced implementation in C). I’ve also been reading up on other interesting projects like Hadoop, HyperTable, Amazon’s SimpleDB, and of course the DB interface for Google’s AppEngine. I’m wondering how these …

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