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A few weeks ago, I made a presentation with the above title at FOSDEM in Brussels. My slides can be found here. The MySQL and Friends devroom had many interesting presentations and the room was full for most of them.

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Hi guys, Early February Oracle released the new version of MySQL named 5.6, one of the enhancements is the GTID (Global Transaction ID)

GTID is an unique identifier which will be added at each transaction, and will be very useful on the slave. remember before we needed to set MASTER_LOG_FILE and MASTER_LOG_POS, now we don’t need them anymore.

Let’s see some new variables which we need to add to our cnf file:
gtid-mode : It will enable GTID, in order to this function work, we need to turn on log-bin and log-slave-updates
enforce-gtid-consistency : It will guarantee that only allowed command will be executed ( more information here)

Basicly, is only this what we need to enable GTID, for this tutorial I will …

When evaluating a MySQL system one of the first things to look at is the MySQL error log. This is defined by the log[_-]error variable in the MySQL Configuration file. Generally found like:

grep log.error /etc/my.cnf
log_error=/var/lib/mysql/logs/mysql_error_log
log-error=/var/lib/mysql/logs/mysql_error_log

It is possible to find multiple rows because this could be defined in the [mysqld] and [mysqld_safe] sections. It is also possible it is incorrectly defined twice in any given section.

Immediately I see a problem here, and the following describes why. If you look at this file name, in this case it’s actually found, but the file is empty.

$ ls -l /var/lib/mysql/logs/mysql_error_log
-rw-r----- 1 mysql mysql 0 Feb 19 20:35 /var/lib/mysql/logs/mysql_error_log

An error log should never exist and be empty, because starting the instance producing messages. An error log could be empty because the system does …

Oracle, MySQL, and SQL Server bloggers are not only sharing their knowledge through their blogs, moreover, they are also learning about themselves. Their posts are cementing their concepts, while opening vistas of new notions. This Log Buffer Edition is yet another vista for their blogs.

Oracle:

Where is Oracle Block Change Tracking today? World’s leading Oracle expert Alex Gorbachev answers.

Marcin Przepiorowski is asking: Oracle on AIX – where’s my cpu time?

Kyle Hailey is monitoring Oracle I/O latency.

How EBS Concurrent Processing should run on Oracle RAC? Pythian’s own …

MySQL 5.6 is believed to be the best MySQL release ever. In order to find out if it is true or not I ran some benchmarks and I am going to share the results with you in this tutorial. Please note that I only tested with default settings (in both cases) and using sysbench as a benchmarking tool, so its a pretty basic test. I highly recommend that you test on your particular workload before upgrading and share your results.

This morning I was planning to check the integrity of a snapshot of a MySQL database that runs on EC2 using EBS, and I accidentally stumbled upon a fast way to quickly find certain types of problems with a backup.

My plan was to use CHECK TABLE on all of the tables to verify the integrity of the backup. The simplest way to run CHECK TABLES on an entire database is like this:

mysqlcheck -c --all-databases

Rather than using that command, I decided to generate a bunch of individual CHECK TABLE statements dynamically by running a query on the information_schema.tables table. Why do it that way? It gives me the flexibility to check a specific schema first, or check the smallest or most frequently updated tables first, etc.

So I ran this command to generate my CHECK TABLE script:

select concat('check table ', table_schema, …

This morning I was planning to check the integrity of a snapshot of a MySQL database that runs on EC2 using EBS, and I accidentally stumbled upon a fast way to quickly find certain types of problems with a backup.

My plan was to use CHECK TABLE on all of the tables to verify the integrity of the backup. The simplest way to run CHECK TABLES on an entire database is like this:

mysqlcheck -c --all-databases

Rather than using that command, I decided to generate a bunch of individual CHECK TABLE statements dynamically by running a query on the information_schema.tables table. Why do it that way? It gives me the flexibility to check a specific schema first, or check the smallest or most frequently updated tables first, etc.

So I ran this command to generate my CHECK TABLE script:

select concat('check table ', table_schema, …

How To Configure Tungsten Connector For Load Balancing, Read/Write Splitting, Automatic Failover And Online Maintenance

As the part of analyzing surprising MySQL 5.5 vs 5.6 performance results I’ve been looking at changes to default variable values. To do that I’ve loaded the values from MySQL 5.5.30 and 5.6.10 to the different tables and ran the query:

mysql [localhost] {msandbox} (test) > select var55.variable_name,left(var55.variable_value,40) value55, left(var56.variable_value,40) var56  from var55 left join var56 on var55.variable_name=var56.variable_name where  var55.variable_value!=var56.variable_value;
+---------------------------------------------------+------------------------------------------+------------------------------------------+
| variable_name                                     | value55                                  | var56                                    | …