While most of the talk recently has mostly been around the new changes in MySQL 5.6 (and that is understandable), I have had lately some very interesting cases to deal with, with respect to the Metadata Locking related changes that were introduced in MySQL 5.5.3. It appears that the implications of Metadata Locking have not been covered well, and since there are still a large number of MySQL 5.0 and 5.1 installations that would upgrade or are in the process of upgrading to MySQL 5.5, I thought it necessary to discuss what these implications exactly are.
To read what Metadata Locking exactly is please read this section here in the MySQL manual.
Let’s start off with having a look at the Meta Data Locking behavior prior to MySQL 5.5.3
Metadata Locking behavior prior to MySQL 5.5.3
Prior to MySQL 5.5.3 a statement that opened a …[Read more]