The following list describes thread State
values that are associated with general query processing and
not more specialized activities such as replication. Many of
these are useful only for finding bugs in the server.
This occurs when the thread creates a table (including internal temporary tables), at the end of the function that creates the table. This state is used even if the table could not be created due to some error.
The thread is calculating a
MyISAM
table key distributions (for example, forANALYZE TABLE
).The thread is checking whether the server has the required privileges to execute the statement.
The thread is performing a table check operation.
The thread has processed one command and is preparing to free memory and reset certain state variables.
The thread is flushing the changed table data to disk and closing the used tables. This should be a fast operation. If not, verify that you do not have a full disk and that the disk is not in very heavy use.
The thread is converting an internal temporary table from a
MEMORY
table to an on-diskMyISAM
table.The thread is processing an
ALTER TABLE
statement. This state occurs after the table with the new structure has been created but before rows are copied into it.If a statement has different
ORDER BY
andGROUP BY
criteria, the rows are sorted by group and copied to a temporary table.The server is copying to a temporary table in memory.
The server is copying to a temporary table on disk. The temporary result set has become too large (see Section 7.4.3.3, “How MySQL Uses Internal Temporary Tables”). Consequently, the thread is changing the temporary table from in-memory to disk-based format to save memory.
The thread is processing
ALTER TABLE ... ENABLE KEYS
for aMyISAM
table.The thread is processing a
SELECT
that is resolved using an internal temporary table.The thread is creating a table. This includes creation of temporary tables.
The thread is creating a temporary table in memory or on disk. If the table is created in memory but later is converted to an on-disk table, the state during that operation will be
Copying to tmp table on disk
.The server is executing the first part of a multiple-table delete. It is deleting only from the first table, and saving columns and offsets to be used for deleting from the other (reference) tables.
deleting from reference tables
The server is executing the second part of a multiple-table delete and deleting the matched rows from the other tables.
The thread is processing an
ALTER TABLE ... DISCARD TABLESPACE
orALTER TABLE ... IMPORT TABLESPACE
statement.This occurs at the end but before the cleanup of
ALTER TABLE
,CREATE VIEW
,DELETE
,INSERT
,SELECT
, orUPDATE
statements.The thread has begun executing a statement.
The thread is executing statements in the value of the
init_command
system variable.The thread has executed a command. Some freeing of items done during this state involves the query cache. This state is usually followed by
cleaning up
.The thread is executing
FLUSH TABLES
and is waiting for all threads to close their tables.The server is preparing to perform a natural-language full-text search.
This occurs before the initialization of
ALTER TABLE
,DELETE
,INSERT
,SELECT
, orUPDATE
statements. Actions taken by the server in this state include flushing the binary log, theInnoDB
log, and some query cache cleanup operations.For the
end
state, the following operations could be happening:Removing query cache entries after data in a table is changed
Writing an event to the binary log
Freeing memory buffers, including for blobs
Someone has sent a
KILL
statement to the thread and it should abort next time it checks the kill flag. The flag is checked in each major loop in MySQL, but in some cases it might still take a short time for the thread to die. If the thread is locked by some other thread, the kill takes effect as soon as the other thread releases its lock.The query is locked by another query.
As of MySQL 5.5.3, this state was removed because it was equivalent to the
Table lock
state and no longer appears inSHOW PROCESSLIST
output.The thread is writing a statement to the slow-query log.
This state is used for the
SHOW PROCESSLIST
state.The initial state for a connection thread until the client has been authenticated successfully.
The server is enabling or disabling a table index.
The thread is trying to open a table. This is should be very fast procedure, unless something prevents opening. For example, an
ALTER TABLE
or aLOCK TABLE
statement can prevent opening a table until the statement is finished. It is also worth checking that yourtable_open_cache
value is large enough.The server is performing initial optimizations for a query.
This state occurs during query optimization.
The thread is removing unneeded relay log files.
This state occurs after processing a query but before the
freeing items
state.The server is reading a packet from the network.
The query was using
SELECT DISTINCT
in such a way that MySQL could not optimize away the distinct operation at an early stage. Because of this, MySQL requires an extra stage to remove all duplicated rows before sending the result to the client.The thread is removing an internal temporary table after processing a
SELECT
statement. This state is not used if no temporary table was created.The thread is renaming a table.
The thread is processing an
ALTER TABLE
statement, has created the new table, and is renaming it to replace the original table.The thread got a lock for the table, but noticed after getting the lock that the underlying table structure changed. It has freed the lock, closed the table, and is trying to reopen it.
The repair code is using a sort to create indexes.
The thread has completed a multi-threaded repair for a
MyISAM
table.The repair code is using creating keys one by one through the key cache. This is much slower than
Repair by sorting
.The thread is rolling back a transaction.
For
MyISAM
table operations such as repair or analysis, the thread is saving the new table state to the.MYI
file header. State includes information such as number of rows, theAUTO_INCREMENT
counter, and key distributions.The thread is doing a first phase to find all matching rows before updating them. This has to be done if the
UPDATE
is changing the index that is used to find the involved rows.Sending data
The thread is processing rows for a
SELECT
statement and also is sending data to the client.The thread is beginning an
ALTER TABLE
operation.The thread is doing a sort to satisfy a
GROUP BY
.The thread is doing a sort to satisfy a
ORDER BY
.The thread is sorting index pages for more efficient access during a
MyISAM
table optimization operation.For a
SELECT
statement, this is similar toCreating sort index
, but for nontemporary tables.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.
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 mysqld servers that are accessing the same tables, you can disable external system locks with the
--skip-external-locking
option. However, external locking is disabled by default, so it is likely that this option will have no effect. ForSHOW PROFILE
, this state means the thread is requesting the lock (not waiting for it).The next thread state after
System lock
. The thread has acquired an external lock and is going to request an internal table lock.This state was replaced in MySQL 5.5.6 with
Waiting for table level lock
.The thread is searching for rows to update and is updating them.
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.
The server is executing the second part of a multiple-table update and updating the matched rows from the other tables.
The thread is going to request or is waiting for an advisory lock requested with a
GET_LOCK()
call. ForSHOW PROFILE
, this state means the thread is requesting the lock (not waiting for it).The thread has invoked a
SLEEP()
call.Waiting for all running commits to finish
A statement that causes an explicit or implicit commit is waiting for release of a read lock. This state was removed in MySQL 5.5.8;
Waiting for commit lock
is used instead.A statement that causes an explicit or implicit commit is waiting for release of a read lock or
FLUSH TABLES WITH READ LOCK
) is waiting for a commit lock. This state was added in MySQL 5.5.8.FLUSH TABLES WITH READ LOCK
) is waiting for a global read lock.Waiting for release of readlock
The thread is waiting for a global read lock obtained by another thread (with
FLUSH TABLES WITH READ LOCK
) to be released. This state was removed in MySQL 5.5.8;Waiting for global read lock
orWaiting for commit lock
are used instead.Waiting for tables
,Waiting for table
,Waiting for table flush
The thread got a notification that the underlying structure for a table has changed and it needs to reopen the table to get the new structure. However, to reopen the table, it must wait until all other threads have closed the table in question.
This notification takes place if another thread has used
FLUSH TABLES
or one of the following statements on the table in question:FLUSH TABLES
,tbl_name
ALTER TABLE
,RENAME TABLE
,REPAIR TABLE
,ANALYZE TABLE
, orOPTIMIZE TABLE
.In MySQL 5.5.6,
Waiting for table
was replaced withWaiting for table flush
.The server is waiting to acquire a lock, where
lock_type
indicates the type of lock:Waiting for event metadata lock
(added in MySQL 5.5.8)Waiting for global metadata lock
(replaced byWaiting for global read lock
in MySQL 5.5.8)Waiting for global read lock
(added in MySQL 5.5.8)Waiting for schema metadata lock
Waiting for stored function metadata lock
Waiting for stored procedure metadata lock
Waiting for table level lock
Waiting for table metadata lock
Waiting for trigger metadata lock
(added in MySQL 5.5.8)
A generic state in which the thread is waiting for a condition to become true. No specific state information is available.
The thread has issued a
FLUSH TABLES WITH READ LOCK
statement to obtain a global read lock and is waiting to obtain the lock. This state was removed in MySQL 5.5.8;Waiting for global read lock
is used instead.The server is writing a packet to the network.