Performance Schema Miscellaneous Tables The default database for the thread, or  NULL  if none has been selected. The type of command the thread is executing on behalf of the client, or  Sleep  if the session is idle. For descriptions of thread commands, see Section 8.14, “Examining Server Thread (Process) Information” . The value of this column corresponds to the  COM_ xxx  commands of the client/server protocol and Com_ xxx  status variables. See Section 5.1.10, “Server Status Variables” The time in seconds that the thread has been in its current state. For a replica SQL thread, the value is the number of seconds between the timestamp of the last replicated event and the real time of the replica host. See Section 17.2.3, “Replication Threads” . An action, event, or state that indicates what the thread is doing. For descriptions of  STATE  values, see Section 8.14, “Examining Server Thread (Process) Information” . Most states correspond to very quick operations. If a thread stays in a given state for many seconds, there might be a problem that needs to be investigated. The statement the thread is executing, or  NULL  if it is executing no statement. The statement might be the one sent to the server, or an innermost statement if the statement executes other statements. For example, if a  CALL  statement executes a stored procedure that is executing a  SELECT  statement, the INFO  value shows the  SELECT  statement. The  processlist  table has these indexes: As mentioned previously, if the  performance_schema_show_processlist  system variable is enabled, the  processlist  table serves as the basis for an alternative implementation of other process information sources: The default  SHOW PROCESSLIST  implementation iterates across active threads from within the thread manager while holding a global mutex. This has negative performance consequences, particularly on busy systems. The alternative  SHOW PROCESSLIST  implementation is based on the Performance Schema processlist  table. This implementation queries active thread data from the Performance Schema rather than the thread manager and does not require a mutex. MySQL configuration affects  processlist  table contents as follows: • COMMAND • TIME • STATE • INFO •Primary key on ( ID ) •The  SHOW PROCESSLIST  statement. •The  mysqladmin processlist  command (which uses  SHOW PROCESSLIST  statement). •Minimum required configuration: •The MySQL server must be configured and built with thread instrumentation enabled. This is true by default; it is controlled using the  DISABLE_PSI_THREAD CMake  option. 5087 TRUNCATE TABLE  is not permitted for the  processlist  table.