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MySQL 5.7 Reference Manual  /  ...  /  The schema_table_lock_waits and x$schema_table_lock_waits Views

26.4.3.28 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.

These views were added in MySQL 5.7.9.

The column descriptions here are brief. For additional information, see the description of the Performance Schema metadata_locks table at Section 25.11.12.1, “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.


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