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Info (Zip) - 4.0Mb The tp_connections Table

The tp_connections table contains one row per connection managed by the Thread Pool plugin. Each row provides information about the current state of a thread pool connection.

The tp_connections table contains the following rows:


    The connection ID as reported by SELECT CONNECTION_ID().


    The index of the thread group in the global array. This column and TP_PROCESSING_THREAD_NUMBER serve as a foreign key into the tp_thread_state table.


    This may be NULL if no thread is currently attached to the connection.


    The Performance Schema thread ID.


    The connection state; this is one of Established, Armed, Queued, Waiting for Credit, Attached, Expired, or Killed.


    When this is 0, the connection is not attached to any worker thread.


    Reports the current stage in the process of killing the connection.


    Reports the current stage in the cleanup process when closing the connection.


    Timestamp showing when the connection last processed a request.


    Timestamp showing when an idle connection will expire if no new request arrives before then; this is NULL when the thread is currently processing a request.


    Timestamp showing when the connection was added to the thread pool's connection request queue.


    Timestamp showing when the connection was dequeued (popped) from the queue by a connection handler thread.


    Timestamp showing when the connection file descriptor was last added to the set monitored by poll() or epoll().


    The index of the connection handler thread in the group which processed the connection request; a higher number means the connection load has triggered the creation of additional connection handler threads.

  • TYPE

    The connection type; this is one of User, Admin_interface or Admin_privilege; Admin_privilege means that this connection had been using the normal interface, but was placed in the admin group due to the user having the TP_CONNECTION_ADMIN privilege.


    The number of queries executed directly by this connection.


    The number of queued queries executed by this connection.


    A timestamp showing when poll_wait() returns with an event for the connection; this value is needed to calculate MANAGEMENT_TIME.


    The accumulated time between the return from waiting on file descriptors; this includes the time spent queued for queries which are not executed directly.