• table_schema 

The schema that contains the table. 

• table_name 

The table that contains the index. 

• index_name 

An index name. 

• non_unique 

The number of nonunique columns in the index. 

• subpart_exists 

Whether the index indexes only part of a column. 

• index_columns 

The name of the columns in the index. 

## 28.4.3.28 The schema_table_lock_waits and x$schema_table_lock_waits Views 

These views display which sessions are blocked waiting on metadata locks, and what is blocking them. 

The column descriptions here are brief. For additional information, see the description of the Performance Schema metadata_locks  table at Section 27.12.13.3, “The metadata_locks Table” . 

The schema_table_lock_waits  and x$schema_table_lock_waits  views have these columns: 

• object_schema 

The schema containing the object to be locked. 

• object_name 

The name of the instrumented object. 

• waiting_thread_id 

The thread ID of the thread that is waiting for the lock. 

• waiting_pid 

The processlist ID of the thread that is waiting for the lock. 

• waiting_account 

The account associated with the session that is waiting for the lock. 

• waiting_lock_type 

The type of the waiting lock. 

• waiting_lock_duration 

How long the waiting lock has been waiting. 

