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Displaying posts with tag: mariadb metadata locks (reset)
Feb
03
2014
Tracking Metadata Locks (MDL) in MariaDB 10.0
Posted by Chris Calender on Mon 03 Feb 2014 23:42 UTC
Tags:

I recently blogged about tracking metadata locks in the latest MySQL, and now I want to discuss how to track these metadata locks in MariaDB.

In MySQL 5.7, there is a table named `metadata_locks` added to the performance_schema (performance_schema must be enabled *and* the metadata_locks instrument must be specifically enabled as well.

In the MariaDB 10.0 implementation (as of 10.0.7), there is a table named METADATA_LOCK_INFO added to the *information_schema*. This is a new plugin, so the plugin must be installed, but that is very simple with: 

INSTALL SONAME 'metadata_lock_info';

Then, you will have the table.

To see it in action:

Connection #1: 

mysql> create table t (id int) engine=myisam;
mysql> begin;
mysql> select * from t;

Connection #2: 

mysql> alter table t add index …
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