30.4.3.28 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 29.12.13.3, “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.

• waiting_query

  The statement that is waiting for the lock.

• waiting_query_secs

  How long the statement has been waiting, in seconds.

• waiting_query_rows_affected

  The number of rows affected by the statement.

• waiting_query_rows_examined

  The number of rows read from storage engines by the statement.

• blocking_thread_id

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

• blocking_pid

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

• blocking_account

  The account associated with the thread that is blocking the waiting lock.

• blocking_lock_type

  The type of lock that is blocking the waiting lock.

• blocking_lock_duration

  How long the blocking lock has been held.

• sql_kill_blocking_query

  The KILL statement to execute to kill the blocking statement.

• sql_kill_blocking_connection

  The KILL statement to execute to kill the session running the blocking statement.