下午发现MySQL，show processlist 发现大量的 waiting for table flush 的select等待操作。
但并没有用户进行lock table的操作。
执行unlock tables后恢复正常。
求解！
error log 发现以下的信息：
Current dir: /data0/mysql/3306/data/
Running threads: 7 Stack size: 196608
Current locks:
lock: 0x2392c410:
lock: 0x239bfe60:
— 省略N多
lock: 0x2aab5433e3f0:
lock: 0x23926a20:
Key caches:
default
Buffer_size: 268435456
Block_size: 1024
Division_limit: 100
Age_limit: 300
blocks used: 20
not flushed: 0
w_requests: 6
writes: 6
r_requests: 11774
reads: 25
handler status:
read_key: 50621628
read_next: 105048552
read_rnd 2053894
read_first: 23079
write: 1252821
delete 2433
update: 61907
Thread database.table_name Locked/Waiting Lock_type
1609 表名 Locked – read Low priority read lock
1609 表名 Locked – read Low priority read lock
1609 表名 Locked – read Low priority read lock
72631 表名 Locked – read Low priority read lock
120409 17:08:25 [Warning] ‘user’ entry ‘root@ ignored in –skip-name-resolve mode.
Memory status:
Non-mmapped space allocated from system: 117252096
Number of free chunks: 403
Number of fastbin blocks: 0
Number of mmapped regions: 18
Space in mmapped regions: 384720896
Maximum total allocated space: 0
Space available in freed fastbin blocks: 0
Total allocated space: 84076496
Total free space: 33175600
Top-most, releasable space: 28180384
Estimated memory (with thread stack): 503349248