Oracle 5.0 Reference Manual page 758

The thread is beginning an
•
Sorting for group
The thread is doing a sort to satisfy a
•
Sorting for order
The thread is doing a sort to satisfy a
•
Sorting index
The thread is sorting index pages for more efficient access during a
operation.
•
Sorting result
For a statement, this is similar to
SELECT
•
statistics
The server is calculating statistics to develop a query execution plan. If a thread is in this state for a
long time, the server is probably disk-bound performing other work.
•
System lock
The thread is going to request or is waiting for an internal or external system lock for the table. If
this state is being caused by requests for external locks and you are not using multiple
servers that are accessing the same
the
--skip-external-locking
so it is likely that this option will have no effect. For
requesting the lock (not waiting for it).
•
Table lock
The next thread state after
request an internal table lock.
•
update
The thread is getting ready to start updating the table.
•
Updating
The thread is searching for rows to update and is updating them.
•
updating main table
The server is executing the first part of a multiple-table update. It is updating only the first table, and
saving columns and offsets to be used for updating the other (reference) tables.
•
updating reference tables
The server is executing the second part of a multiple-table update and updating the matched rows
from the other tables.
•
User lock
The thread is going to request or is waiting for an advisory lock requested with a
[965] call. For
GET_LOCK()
(not waiting for it).
•
Waiting for release of readlock
General Thread States
operation.
ALTER TABLE
GROUP BY.
ORDER BY.
Creating sort
tables, you can disable external system locks with
MyISAM
[420] option. However, external locking is disabled by default,
lock. The thread has acquired an external lock and is going to
System
PROFILE, this state means the thread is requesting the lock
SHOW
738
MyISAM
index, but for nontemporary tables.
PROFILE, this state means the thread is
SHOW
table optimization
mysqld