mysql show processlist state

这个命令中最关键的就是state列，mysql列出的状态主要有以下几种：
　　Checking table

　正在检查数据表（这是自动的）。

　Closing tables

　正在将表中修改的数据刷新到磁盘中，同时正在关闭已经用完的表。这是一个很快的操作，如果不是这样的话，就应该确认磁盘空间是否已经满了或者磁盘是否正处于重负中。

　Connect Out

　复制从服务器正在连接主服务器。

　Copying to tmp table on disk

　由于临时结果集大于tmp_table_size，正在将临时表从内存存储转为磁盘存储以此节省内存。

　Creating tmp table

　正在创建临时表以存放部分查询结果。

　deleting from main table

　服务器正在执行多表删除中的第一部分，刚删除第一个表。

　deleting from reference tables

　服务器正在执行多表删除中的第二部分，正在删除其他表的记录。

　Flushing tables

　正在执行FLUSH TABLES，等待其他线程关闭数据表。

　Killed

　发送了一个kill请求给某线程，那么这个线程将会检查kill标志位，同时会放弃下一个kill请求。MySQL会在每次的主循环中检查kill标志位，不过有些情况下该线程可能会过一小段才能死掉。如果该线程程被其他线程锁住了，那么kill请求会在锁释放时马上生效。

　Locked

　被其他查询锁住了。

　Sending data

　正在处理SELECT查询的记录，同时正在把结果发送给客户端。

　Sorting for group

　正在为GROUP BY做排序。

　Sorting for order

　正在为ORDER BY做排序。

　Opening tables

　这个过程应该会很快，除非受到其他因素的干扰。例如，在执ALTER TABLE或LOCK TABLE语句行完以前，数据表无法被其他线程打开。正尝试打开一个表。

　Removing duplicates

　正在执行一个SELECT DISTINCT方式的查询，但是MySQL无法在前一个阶段优化掉那些重复的记录。因此，MySQL需要再次去掉重复的记录，然后再把结果发送给客户端。

　Reopen table

　获得了对一个表的锁，但是必须在表结构修改之后才能获得这个锁。已经释放锁，关闭数据表，正尝试重新打开数据表。

　Repair by sorting

　修复指令正在排序以创建索引。

　Repair with keycache

　修复指令正在利用索引缓存一个一个地创建新索引。它会比Repair by sorting慢些。

　Searching rows for update

　正在讲符合条件的记录找出来以备更新。它必须在UPDATE要修改相关的记录之前就完成了。

　Sleeping

　正在等待客户端发送新请求.

　System lock

　正在等待取得一个外部的系统锁。如果当前没有运行多个mysqld服务器同时请求同一个表，那么可以通过增加--skip-external-locking参数来禁止外部系统锁。

　Upgrading lock

　INSERT DELAYED正在尝试取得一个锁表以插入新记录。

　Updating

　正在搜索匹配的记录，并且修改它们。

　User Lock

　正在等待GET_LOCK()。

　Waiting for tables

　该线程得到通知，数据表结构已经被修改了，需要重新打开数据表以取得新的结构。然后，为了能的重新打开数据表，必须等到所有其他线程关闭这个表。以下几种情况下会产生这个通知：FLUSH TABLES tbl_name, ALTER TABLE, RENAME TABLE, REPAIR TABLE, ANALYZE TABLE,或OPTIMIZE TABLE。

　waiting for handler insert

　INSERT DELAYED已经处理完了所有待处理的插入操作，正在等待新的请求。

　大部分状态对应很快的操作，只要有一个线程保持同一个状态好几秒钟，那么可能是有问题发生了，需要检查一下。

　还有其他的状态没在上面中列出来，不过它们大部分只是在查看服务器是否有存在错误是才用得着。

After create

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.

Analyzing

The thread is calculating a

MyISAM

table key distributions (for example, for

ANALYZE
TABLE

).

checking permissions

The thread is checking whether the server has the required privileges to execute the statement.

Checking table

The thread is performing a table check operation.

cleaning up

The thread has processed one command and is preparing to free memory and reset certain state variables.

closing tables

The thread is flushing the changed table data to disk and closing the used tables. This should be a fast operation. If not, you should verify that you do not have a full disk and that the disk is not in very heavy use.

converting HEAP to MyISAM

The thread is converting an internal temporary table from a

MEMORY

table to an on-disk

MyISAM

table.

copy to tmp 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.

Copying to group table

If a statement has different

ORDER BY

and

GROUP BY

criteria, the rows are sorted by group and copied to a temporary table.

Copying to tmp table

The server is copying to a temporary table in memory.

Copying to tmp table on disk

The server is copying to a temporary table on disk. The temporary result set was larger than

tmp_table_size

and
the thread is changing the temporary table from in-memory to disk-based format to save memory.

Creating index

The thread is processing

ALTER TABLE ... ENABLE KEYS

for a

MyISAM

table.

Creating sort index

The thread is processing a

SELECT

that is resolved using an internal temporary table.

creating table

The thread is creating a table. This includes creation of temporary tables.

Creating tmp table

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

.

deleting from main table

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.

discard_or_import_tablespace

The thread is processing an

ALTER TABLE ... DISCARD TABLESPACE

or

ALTER TABLE ... IMPORT TABLESPACE

statement.

end

This occurs at the end but before the cleanup of

ALTER TABLE

,

CREATE
VIEW

,

DELETE

,

INSERT

,

SELECT

,
or

UPDATE

statements.

executing

The thread has begun executing a statement.

Execution of init_command

The thread is executing statements in the value of the

init_command

system variable.

freeing items

The thread has executed a command. This state is usually followed by

cleaning up

.

Flushing tables

The thread is executing

FLUSH TABLES

and is waiting for all threads to close their tables.

FULLTEXT initialization

The server is preparing to perform a natural-language full-text search.

init

This occurs before the initialization of

ALTER TABLE

,

DELETE

,

INSERT

,

SELECT

,
or

UPDATE

statements.

Killed

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.

Locked

The query is locked by another query.

logging slow query

The thread is writing a statement to the slow-query log.

NULL

This state is used for the

SHOW PROCESSLIST

state.

login

The initial state for a connection thread until the client has been authenticated successfully.

Opening
tables

,

Opening table

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 a

LOCK TABLE

statement can prevent opening
a table until the statement is finished.

preparing

This state occurs during query optimization.

Purging old relay logs

The thread is removing unneeded relay log files.

query end

This state occurs after processing a query but before the

freeing items

state.

Reading from net

The server is reading a packet from the network.

Removing duplicates

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.

removing tmp table

The thread is removing an internal temporary table after processing a

SELECT

statement. This state
is not used if no temporary table was created.

rename

The thread is renaming a table.

rename result table

The thread is processing an

ALTER TABLE

statement, has created the new table, and is
renaming it to replace the original table.

Reopen tables

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.

Repair by sorting

The repair code is using a sort to create indexes.

Repair done

The thread has completed a multi-threaded repair for a

MyISAM

table.

Repair with keycache

The repair code is using creating keys one by one through the key cache. This is much slower than

Repair by sorting

.

Rolling back

The thread is rolling back a transaction.

Saving state

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, the

AUTO_INCREMENT

counter, and key distributions.

Searching rows for update

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.

setup

The thread is beginning an

ALTER TABLE

operation.

Sorting for group

The thread is doing a sort to satisfy a

GROUP BY

.

Sorting for order

The thread is doing a sort to satisfy a

ORDER BY

.

Sorting index

The thread is sorting index pages for more efficient access during a

MyISAM

table optimization operation.

Sorting result

For a

SELECT

statement, this is similar to

Creating sort index

, but for nontemporary
tables.

statistics

The server is calculating statistics to develop a query execution plan.

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 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. For

SHOW
PROFILE

, this state means the thread is requesting the lock (not waiting for it).

Table lock

The next thread state after

System lock

. The thread has acquired an external lock and is going to request an internal table lock.

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

GET_LOCK()

call.
For

SHOW PROFILE

, this state means the thread is requesting the lock (not waiting
for it).

Waiting
for tables

,

Waiting for table

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
, [code]ALTER
TABLE

,

RENAME TABLE

,

REPAIR
TABLE

,

ANALYZE TABLE

, or

OPTIMIZE
TABLE

.

Waiting on cond

A generic state in which the thread is waiting for a condition to become true. No specific state information is available.

Writing to net

The server is writing a packet to the network.