A lock is a mechanism associated with a table used to restrict the unauthorized access of the data in a table. MySQL allows a client session to acquire a table lock explicitly to cooperate with other sessions to access the table’s data.

What does it mean when a database is locked?

A clinical trial term of art for an action taken to prevent further changes to the trial database. A database is locked after review, query resolution and determination that it is ready for analysis.

How can I tell if a MySQL table is locked?

In MySQL, locked tables are identified using the SHOW OPEN TABLES command. In its simplest form is displays all locked tables. All open tables in the table cache are listed, but the IN_USE column indicates of the table is locked. When the first lock is taken, the value increments to 1.