The PROCESSLIST table provides
information about which threads are running.
INFORMATION_SCHEMA Name | SHOW Name | Remarks |
|---|---|---|
ID | Id | MySQL extension |
USER | User | MySQL extension |
HOST | Host | MySQL extension |
DB | db | MySQL extension |
COMMAND | Command | MySQL extension |
TIME | Time | MySQL extension |
STATE | State | MySQL extension |
INFO | Info | MySQL extension |
For an extensive description of the table columns, see Section 13.7.5.30, “SHOW PROCESSLIST Syntax”.
Notes:
The PROCESSLIST table is a
nonstandard table.
Like the output from the corresponding
SHOW statement, the
PROCESSLIST table will only show
information about your own threads, unless you have the
PROCESS privilege, 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.threads table.
However, access to threads does
not require a mutex and has minimal impact on server
performance.
INFORMATION_SCHEMA.PROCESSLIST
and SHOW PROCESSLIST have
negative performance consequences because they require a
mutex. threads also shows
information about background threads, which
INFORMATION_SCHEMA.PROCESSLIST
and SHOW PROCESSLIST do not.
This means that threads can be
used to monitor activity the other thread information sources
cannot.
The following statements are equivalent:
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST SHOW FULL PROCESSLIST