Pre-General Availability Draft: 2018-01-12
PROCESSLIST table provides
information about which threads are running.
For an extensive description of the table columns, see Section 220.127.116.11, “SHOW PROCESSLIST Syntax”.
PROCESSLISTtable is a nonstandard table.
Like the output from the corresponding
PROCESSLISTtable will only show information about your own threads, unless you have the
PROCESSprivilege, in which case you will see information about other threads, too. As an anonymous user, you cannot see any rows at all.
If an SQL statement refers to
INFORMATION_SCHEMA.PROCESSLIST, MySQL populates the entire table once, when statement execution begins, so there is read consistency during the statement. There is no read consistency for a multi-statement transaction, though.
Process information is also available from the
performance_schema.threadstable. However, access to
threadsdoes not require a mutex and has minimal impact on server performance.
SHOW PROCESSLISThave negative performance consequences because they require a mutex.
threadsalso shows information about background threads, which
SHOW PROCESSLISTdo not. This means that
threadscan be used to monitor activity the other thread information sources cannot.
The following statements are equivalent:
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST SHOW FULL PROCESSLIST