Syntax
------ 
SHOW OPEN TABLES [FROM db_name]
 [LIKE 'pattern' | WHERE expr]
 
Description
----------- 
 SHOW OPEN TABLES lists the non-TEMPORARY
tables that are currently open in the table cache. See
http://dev.mysql.com/doc/refman/5.1/en/table-cache.html.
 
The FROM and LIKE clauses may be used.
 
The FROM
clause, if present, restricts the tables shown to those
present in the
db_name database. 
 
The LIKE clause, if
present on its own, indicates which table names to match.
The WHERE and LIKE clauses can be given to select rows using
more general conditions, as discussed in Extended SHOW.
 
The following information is returned:
 
Column | Description | 
 
Database | Database name. | 
 
Name | Table name. | 
 
In_use | Number of table instances being used. | 
 
Name_locked | 1 if the table is name-locked, e.g. if it is
being dropped or renamed, otherwise 0. | 
 
Before MariaDB 5.5, each use of, for example, LOCK TABLE ...
WRITE would increment In_use for that table. With the
implementation of the metadata locking improvements in
MariaDB 5.5, LOCK TABLE... WRITE acquires a strong MDL lock,
and concurrent connections will wait on this MDL lock, so
any subsequent LOCK TABLE... WRITE will not increment
In_use.
 
Example
 
SHOW OPEN TABLES;
 
+----------+---------------------------+--------+-------------+
| Database | Table | In_use | Name_locked |
+----------+---------------------------+--------+-------------+
...
| test | xjson | 0 | 0 |
| test | jauthor | 0 | 0 |
| test | locks | 1 | 0 |
...
+----------+---------------------------+--------+-------------+
 

 
 
 
 
 
 
 

URL: https://mariadb.com/kb/en/show-open-tables/