Working on large upgrade of MySQL 4.1 running Innodb to MySQL 5.0 and doing oprofile analyzes we found very interesting issue of buf_get_latched_pages_number being responsible for most CPU usage. It did not look right.

The close look revealed this is the function which is used to compute number of latched pages in Innodb Buffer Pool, which is called when you run SHOW INNODB STATUS and SHOW STATUS. In this case for same of monitoring SHOW GLOBAL STATUS was run every couple of seconds being considered fast operation, as it is in MySQL 4.1

But why buf_get_latched_pages_number ? Because this function traverses whole buffer pool to compute number of latched pages, which is quite slow with buffer pools containing millions of pages. But even worse this is done while holding global buffer pool mutex.

Another …

Submitting patches to Open Source code doesn't come naturally to everyone. It is not easy, since it requires coding skills that the average user does not have. Moreover, code patches require a fair amount of additional documentation, without which the patch itself is virtually useless. These notes will walk you through the requirements of a good patch for MySQL server and perhaps other projects.

Introduction

Using Eclipse, we'll develop an example application that will document key structures, and demonstrate several API calls. This article will also cover configuring Ubuntu and Eclipse for MySQL client development. Let's get going...

Ubuntu

You'll need to install the build-essential, Eclipse and the Eclipse CDT packages:





MySQL

In order to develop an application with the API, you'll need libmysqlclient and all the header files installed.


…

Recently mysqlnd, the MySQL native driver for PHP, has been checked in to the PHP 6 (HEAD) development tree on cvs.php.net. This blog posting gives a quick overview how you can build PHP 5 and PHP 6 with mysqlnd support.

What mysqlnd is and what not

If you do not know what mysqlnd is or not is, read up the details on http://dev.mysql.com/downloads/connector/php-mysqlnd/. In short: mysqlnd is is a replacement for the libmysql, the MySQL Client Library. It it closely integrated into PHP and it is distributed under the terms of the PHP license. You can now …

Recently mysqlnd, the MySQL native driver for PHP, has been checked in to the PHP 6 (HEAD) development tree on cvs.php.net. This blog posting gives a quick overview how you can build PHP 5 and PHP 6 with mysqlnd support.

What mysqlnd is and what not

If you do not know what mysqlnd is or not is, read up the details on http://dev.mysql.com/downloads/connector/php-mysqlnd/. In short: mysqlnd is is a replacement for the libmysql, the MySQL Client Library. It it closely integrated into PHP and it is distributed under the terms of the PHP license. You can now …

The 55th edition of Log Buffer, the weekly review of database blogs, is published on the Ardent Performance Computing Blog, thanks to Jeremy Schneider. Hasan Tonguç Yilmaz’s Oracle Blog takes next week’s LB. Please send an email to the Log Buffer administrator if you’d like to edit and publish an edition of your own. Jeremy Schneider’s [...]

Is your MySQL server doing an extra index scan on queries that need to check a key for matches or NULL? It's easy for this to happen accidentally, but it's also easy to fix, especially in MySQL 5.0 and up. Here's how.

With some effort just before my holiday, I have managed to complete the release of the next version of MyBS, the BLOB streaming engine for MySQL.

This version includes all the basic functionality required to stream BLOB data in and out of MySQL tables.

The main features are:

• Uploading of BLOB data directly into the database using HTTP PUT or GET methods.
  
• Downloaded of BLOB data directly from the database using HTTP GET.
  
• BLOB size may exceed 4GB - theoretical BLOB size limit of 256 Terabytes.
  
• BLOBs are stored in a repository which manages references from other storage engine tables.
  
• BLOBs are referenced by a URL.
  
• URLs referencing BLOBs in the repository have a unique access code, for security.
  
• The theoretical maximum repository size is 4 Zettabytes (2^72 bytes) per …

It is true you might be better of being unaware about problems, because in this case you might not run into them
Just couple of days ago Kaj Arno told me there are issues reported with SHOW PROFILE patch available in latest MySQL Community Edition and I've been troubleshooting customer affected by one of these very issues today.

The Bug can dramatically increase System CPU usage (about 10 times in this case)

The "fix" was to get MySQL 5.0.44 sources from Dorsal Source which base

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