Ever see this
TCP: drop open request from 10.209.23.142/43407

Well lets start with a more specific example:
Memcache is tightly coupled in your code: Every request caches the response from the database so a lot of quick calls to memcache is made. Then you start adding full HTML to memcache instead of just caching the raw data; so now your load pattern is bigger blobs of data still at a high request rate.

Now suddenly the memcache port hangs-you verify this by ssh to the box and then telneting the the memcache box port 11211 and see that ssh works (port 22) yet 11211 does not. As a result all your front ends fall over because they are hanging on the memcache port.

THIS IS NOT A MEMCACHE PROBLEM. Its a kernel problem. Default installs of Linux set the TCP window buffer size to a desktop setting and not a server setting.

So I run this script.

 …

I put it to you... should the datagrid support arrays as the data source as well as MySQL result sets? I'm thinking maybe it should, mainly because I need something to do. :-/ But I can see the situation where you might want to test and setup the datagrid by just giving it an array, before you actually set it up correctly for MySQL. Or maybe there's connection issues and you want to make sure that the datagrid isn't the problem. But regardless, should the datagrid support arrays?

One of our peer group developers contacted me today stating that they were inserting a value of 10 in one of the columns in their tables. But after the insert, when they query the table they were getting the value as 0.

Logged into the box to check what was happening. Luckily binlog was turned on that mysql instance. Ran the mysqlbinlog utility on the current binlog and greped for the particular primary key value.

It listed an insert statement and an update statement. There was the culprit, the value of 10 was getting inserted but soon the application was following it up with an update to value 0. Yeah it is always not the database

…

Running MySQL 4 And MySQL 5 Concurrently

This tutorial shows how to install MySQL 5 on a system where MySQL 4 is already running. It also shows how to configure phpMyAdmin to use both databases.

I put it to you... should the datagrid support arrays as the data source as well as MySQL result sets? I'm thinking maybe it should, mainly because I need something to do. :-/ But I can see the situation where you might want to test and setup the datagrid by just giving it an array, before you actually set it up correctly for MySQL. Or maybe there's connection issues and you want to make sure that the datagrid isn't the problem. But regardless, should the datagrid support arrays?

Contemporary software engineering models include many loosely-defined layers. Database developers might help with other layers, but for the most part a database administrator’s domain is the persistence layer.

• 
  
• Presentation
  
• Application
  
• Business Logic
  
• Persistence (also called Storage)
  

The Daily WTF has an article on The Mythical Business Layer makes the case for not separating the business layer and the application layer:

A good system (as in, one that’s maintainable by other people) has no choice but to duplicate, triplicate, or even-more-licate business logic. If Account_Number is a seven-digit required field, it should be declared as CHAR(7) NOT NULL in the database and …

Update: Karanbir says “Just one thing to keep in mind is that we dont want too many people using it from the Testing repository - we only need enough feedback to move it from testing to stable ( and to be honest, there are already 8 people who have said yes it works - so move to stable should happen within the next 24 - 48 hrs ). Once the package is in stable, users on CentOS4 and 5 wont need to do anything more than just ‘yum install maatkit’ and it will install for them.”

At least one person (Karanbir Singh) is working to get Maatkit into the CentOS repositories, and I believe there might be movement towards RHEL also. From an email to the Maatkit discussion list a little while ago,

I am in the process of getting maatkit into the CentOS-Extras …

When we write about investors on this blog we are normally referring to angel and VC investors and the funding they provide to open source start-ups. There is a small, but growing, list of VCs that clearly understand the open source development and distribution models and the long-term profit potential of open source software vendors.

Can the same be said of individual and institutional investors buying and selling shares in publicly traded software companies? Not according to the analysis of Oliver Alexy, a research assistant and doctoral candidate at the Technische Universität München TUM Business School in Munich, Germany.

Oliver has analyzed the impact that releasing software under open source licenses has on a company’s share price. Details have been published this week in the …

Running MySQL 4 And MySQL 5 Concurrently

This tutorial shows how to install MySQL 5 on a system where MySQL 4 is already running. It also shows how to configure phpMyAdmin to use both databases.

I was poking around the MySQL Worklog again over the weekend, and found a request for materialized views for MySQL. This feature has existed in Oracle for a while, in DB2 as a materialized query table, and appeared in MS SQL Server 2000 and 2005 as indexed views.

What is a materialized view?

A materialized view is a database object that contains the results of a query. The FROM clause of the query can name tables, views, and other materialized views. (from Oracle).

Essentially a materialized view …