MetaData Lock 杨奇龙 ---MYSQL博客专家
http://blog.itpub.net/22664653/viewspace-1791608/
http://blog.csdn.net/dba_waterbin/article/details/17371937
实验1:
mysql> show create table t;
+-------+------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+------------------------------------------------------------------------------------+
| t | CREATE TABLE `t` (
`a` int() DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+------------------------------------------------------------------------------------+
row in set (0.18 sec)
mysql> select @@tx_isolation;
+-----------------+
| @@tx_isolation |
+-----------------+
| REPEATABLE-READ |
+-----------------+
row in set (0.00 sec)
insert into t select ;
insert into t select ;
会话1：事物未提交
mysql> begin;
Query OK, rows affected (0.00 sec) mysql> select * from t where a=;
+------+
| a |
+------+
| |
+------+
row in set (0.19 sec)
会话2：执行DDL语句
mysql> alter table t add column comment varchar() default ""; //阻塞了
会话3：
mysql> show processlist;
+----+------+-----------+------+---------+------+---------------------------------+-------------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+---------------------------------+-------------------------------------------------------------+
| 1 | root | localhost | test | Sleep | 418 | | NULL |
| 2 | root | localhost | test | Query | 359 | Waiting for table metadata lock | alter table t add column comment varchar(200) default "123" |
| 3 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+---------------------------------+-------------------------------------------------------------+
GDB 调试：
[root@localhost test]# gdb -p 4373 //全部线程中断了
(gdb) info threads
Id Target Id Frame
25 Thread 0x7f9c20367940 (LWP 4374) 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
24 Thread 0x7f9c1fb66940 (LWP 4375) 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
23 Thread 0x7f9c1f365940 (LWP 4376) 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
22 Thread 0x7f9c1eb64940 (LWP 4377) 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
21 Thread 0x7f9c1e363940 (LWP 4378) 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
20 Thread 0x7f9c1db62940 (LWP 4379) 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
19 Thread 0x7f9c1d361940 (LWP 4380) 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
18 Thread 0x7f9c1cb60940 (LWP 4381) 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
17 Thread 0x7f9c1c35f940 (LWP 4382) 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
16 Thread 0x7f9c1bb5e940 (LWP 4383) 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
15 Thread 0x7f9c1ab5c940 (LWP 4386) 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
14 Thread 0x7f9c19910940 (LWP 4387) 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
13 Thread 0x7f9c1910f940 (LWP 4388) 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
12 Thread 0x7f9c1890e940 (LWP 4389) 0x00007f9c7ed39172 in select () from /lib64/libc.so.6
11 Thread 0x7f9c1810d940 (LWP 4390) 0x00007f9c7f897019 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
10 Thread 0x7f9c1b35d940 (LWP 4391) 0x00007f9c7ed39172 in select () from /lib64/libc.so.6
9 Thread 0x7f9c1790c940 (LWP 4392) 0x00007f9c7f897019 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
8 Thread 0x7f9c0ffff940 (LWP 4393) 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
7 Thread 0x7f9c1710b940 (LWP 4394) 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
6 Thread 0x7f9c1690a940 (LWP 4395) 0x00007f9c7f89a9c8 in do_sigwait () from /lib64/libpthread.so.0
5 Thread 0x7f9c168c8940 (LWP 5335) 0x00007f9c7ed370b6 in poll () from /lib64/libc.so.6
4 Thread 0x7f9c16887940 (LWP 5367) 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
3 Thread 0x7f9c16846940 (LWP 5408) 0x00007f9c7f897019 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
2 Thread 0x7f9c16805940 (LWP 5684) 0x00007f9c7f897019 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
* 1 Thread 0x7f9c7fcaa6f0 (LWP 4373) 0x00007f9c7ed370b6 in poll () from /lib64/libc.so.6
(gdb)
(gdb) thread apply all bt Thread 25 (Thread 0x7f9c20367940 (LWP 4374)):
#0 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
#1 0x0000000000ba441d in os_aio_linux_collect (array=0x1988ee0, segment=0, seg_size=256) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:4975
#2 0x0000000000ba4be2 in os_aio_linux_handle (global_seg=0, message1=0x7f9c203670e0, message2=0x7f9c203670d8, type=0x7f9c203670d0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:5119
#3 0x0000000000d4deca in fil_aio_wait (segment=0) at /usr/src/mysql-5.6.28/storage/innobase/fil/fil0fil.cc:5796
#4 0x0000000000c6e122 in io_handler_thread (arg=0x1829c20 <n>) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0start.cc:492
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 24 (Thread 0x7f9c1fb66940 (LWP 4375)):
#0 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
#1 0x0000000000ba441d in os_aio_linux_collect (array=0x197bc40, segment=0, seg_size=256) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:4975
#2 0x0000000000ba4be2 in os_aio_linux_handle (global_seg=1, message1=0x7f9c1fb660e0, message2=0x7f9c1fb660d8, type=0x7f9c1fb660d0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:5119
#3 0x0000000000d4deca in fil_aio_wait (segment=1) at /usr/src/mysql-5.6.28/storage/innobase/fil/fil0fil.cc:5796
#4 0x0000000000c6e122 in io_handler_thread (arg=0x1829c28 <n+8>) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0start.cc:492
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 23 (Thread 0x7f9c1f365940 (LWP 4376)):
#0 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
#1 0x0000000000ba441d in os_aio_linux_collect (array=0x1973980, segment=0, seg_size=256) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:4975
#2 0x0000000000ba4be2 in os_aio_linux_handle (global_seg=2, message1=0x7f9c1f3650e0, message2=0x7f9c1f3650d8, type=0x7f9c1f3650d0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:5119
#3 0x0000000000d4deca in fil_aio_wait (segment=2) at /usr/src/mysql-5.6.28/storage/innobase/fil/fil0fil.cc:5796
#4 0x0000000000c6e122 in io_handler_thread (arg=0x1829c30 <n+16>) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0start.cc:492
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 22 (Thread 0x7f9c1eb64940 (LWP 4377)):
#0 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
#1 0x0000000000ba441d in os_aio_linux_collect (array=0x1973980, segment=1, seg_size=256) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:4975
#2 0x0000000000ba4be2 in os_aio_linux_handle (global_seg=3, message1=0x7f9c1eb640e0, message2=0x7f9c1eb640d8, type=0x7f9c1eb640d0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:5119
#3 0x0000000000d4deca in fil_aio_wait (segment=3) at /usr/src/mysql-5.6.28/storage/innobase/fil/fil0fil.cc:5796
#4 0x0000000000c6e122 in io_handler_thread (arg=0x1829c38 <n+24>) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0start.cc:492
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 21 (Thread 0x7f9c1e363940 (LWP 4378)):
#0 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
#1 0x0000000000ba441d in os_aio_linux_collect (array=0x1973980, segment=2, seg_size=256) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:4975
#2 0x0000000000ba4be2 in os_aio_linux_handle (global_seg=4, message1=0x7f9c1e3630e0, message2=0x7f9c1e3630d8, type=0x7f9c1e3630d0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:5119
#3 0x0000000000d4deca in fil_aio_wait (segment=4) at /usr/src/mysql-5.6.28/storage/innobase/fil/fil0fil.cc:5796
#4 0x0000000000c6e122 in io_handler_thread (arg=0x1829c40 <n+32>) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0start.cc:492
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 20 (Thread 0x7f9c1db62940 (LWP 4379)):
#0 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
#1 0x0000000000ba441d in os_aio_linux_collect (array=0x1973980, segment=3, seg_size=256) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:4975
#2 0x0000000000ba4be2 in os_aio_linux_handle (global_seg=5, message1=0x7f9c1db620e0, message2=0x7f9c1db620d8, type=0x7f9c1db620d0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:5119
#3 0x0000000000d4deca in fil_aio_wait (segment=5) at /usr/src/mysql-5.6.28/storage/innobase/fil/fil0fil.cc:5796
#4 0x0000000000c6e122 in io_handler_thread (arg=0x1829c48 <n+40>) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0start.cc:492
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 19 (Thread 0x7f9c1d361940 (LWP 4380)):
#0 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
#1 0x0000000000ba441d in os_aio_linux_collect (array=0x19961a0, segment=0, seg_size=256) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:4975
#2 0x0000000000ba4be2 in os_aio_linux_handle (global_seg=6, message1=0x7f9c1d3610e0, message2=0x7f9c1d3610d8, type=0x7f9c1d3610d0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:5119
#3 0x0000000000d4deca in fil_aio_wait (segment=6) at /usr/src/mysql-5.6.28/storage/innobase/fil/fil0fil.cc:5796
#4 0x0000000000c6e122 in io_handler_thread (arg=0x1829c50 <n+48>) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0start.cc:492
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 18 (Thread 0x7f9c1cb60940 (LWP 4381)):
#0 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
#1 0x0000000000ba441d in os_aio_linux_collect (array=0x19961a0, segment=1, seg_size=256) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:4975
#2 0x0000000000ba4be2 in os_aio_linux_handle (global_seg=7, message1=0x7f9c1cb600e0, message2=0x7f9c1cb600d8, type=0x7f9c1cb600d0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:5119
#3 0x0000000000d4deca in fil_aio_wait (segment=7) at /usr/src/mysql-5.6.28/storage/innobase/fil/fil0fil.cc:5796
#4 0x0000000000c6e122 in io_handler_thread (arg=0x1829c58 <n+56>) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0start.cc:492
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 17 (Thread 0x7f9c1c35f940 (LWP 4382)):
#0 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
#1 0x0000000000ba441d in os_aio_linux_collect (array=0x19961a0, segment=2, seg_size=256) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:4975
#2 0x0000000000ba4be2 in os_aio_linux_handle (global_seg=8, message1=0x7f9c1c35f0e0, message2=0x7f9c1c35f0d8, type=0x7f9c1c35f0d0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:5119
#3 0x0000000000d4deca in fil_aio_wait (segment=8) at /usr/src/mysql-5.6.28/storage/innobase/fil/fil0fil.cc:5796
#4 0x0000000000c6e122 in io_handler_thread (arg=0x1829c60 <n+64>) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0start.cc:492
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 16 (Thread 0x7f9c1bb5e940 (LWP 4383)):
#0 0x00000030738005b4 in ?? () from /usr/lib64/libaio.so.1
#1 0x0000000000ba441d in os_aio_linux_collect (array=0x19961a0, segment=3, seg_size=256) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:4975
#2 0x0000000000ba4be2 in os_aio_linux_handle (global_seg=9, message1=0x7f9c1bb5e0e0, message2=0x7f9c1bb5e0d8, type=0x7f9c1bb5e0d0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0file.cc:5119
#3 0x0000000000d4deca in fil_aio_wait (segment=9) at /usr/src/mysql-5.6.28/storage/innobase/fil/fil0fil.cc:5796
#4 0x0000000000c6e122 in io_handler_thread (arg=0x1829c68 <n+72>) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0start.cc:492
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 15 (Thread 0x7f9c1ab5c940 (LWP 4386)):
#0 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000baa77b in os_cond_wait_timed (cond=0x4766d10, fast_mutex=0x4766cd0, abstime=0x7f9c1ab5c0c0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:177
#2 0x0000000000baa9b0 in os_event_wait_time_low (event=0x4766cd0, time_in_usec=1000000, reset_sig_count=1) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:705
#3 0x0000000000b88945 in lock_wait_timeout_thread (arg=0x0) at /usr/src/mysql-5.6.28/storage/innobase/lock/lock0wait.cc:503
#4 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#5 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#6 0x0000000000000000 in ?? () Thread 14 (Thread 0x7f9c19910940 (LWP 4387)):
#0 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000baa77b in os_cond_wait_timed (cond=0x194ebc0, fast_mutex=0x194eb80, abstime=0x7f9c19910080) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:177
#2 0x0000000000baa9b0 in os_event_wait_time_low (event=0x194eb80, time_in_usec=1000000, reset_sig_count=1) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:705
#3 0x0000000000c65ce8 in srv_error_monitor_thread (arg=0x0) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0srv.cc:1769
#4 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#5 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#6 0x0000000000000000 in ?? () Thread 13 (Thread 0x7f9c1910f940 (LWP 4388)):
#0 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000baa77b in os_cond_wait_timed (cond=0x194ec50, fast_mutex=0x194ec10, abstime=0x7f9c1910f090) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:177
#2 0x0000000000baa9b0 in os_event_wait_time_low (event=0x194ec10, time_in_usec=5000000, reset_sig_count=1) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:705
#3 0x0000000000c66e58 in srv_monitor_thread (arg=0x0) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0srv.cc:1538
#4 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#5 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#6 0x0000000000000000 in ?? () Thread 12 (Thread 0x7f9c1890e940 (LWP 4389)):
#0 0x00007f9c7ed39172 in select () from /lib64/libc.so.6
#1 0x0000000000bab334 in os_thread_sleep (tm=1000000) at /usr/src/mysql-5.6.28/storage/innobase/os/os0thread.cc:261
#2 0x0000000000c64c96 in srv_master_sleep () at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0srv.cc:2300
#3 0x0000000000c65853 in srv_master_thread (arg=0x0) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0srv.cc:2344
#4 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#5 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#6 0x0000000000000000 in ?? () Thread 11 (Thread 0x7f9c1810d940 (LWP 4390)):
#0 0x00007f9c7f897019 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000baaa63 in os_cond_wait (cond=0x194eb30, fast_mutex=0x194eaf0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:214
#2 0x0000000000baaadf in os_event_wait_low (event=0x194eaf0, reset_sig_count=4) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:592
#3 0x0000000000c64129 in srv_purge_coordinator_suspend (slot=0x194ea20, rseg_history_len=653) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0srv.cc:2634
#4 0x0000000000c64639 in srv_purge_coordinator_thread (arg=0x0) at /usr/src/mysql-5.6.28/storage/innobase/srv/srv0srv.cc:2753
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 10 (Thread 0x7f9c1b35d940 (LWP 4391)):
#0 0x00007f9c7ed39172 in select () from /lib64/libc.so.6
#1 0x0000000000bab334 in os_thread_sleep (tm=1000000) at /usr/src/mysql-5.6.28/storage/innobase/os/os0thread.cc:261
#2 0x0000000000cf9215 in page_cleaner_sleep_if_needed (next_loop_time=1467172254235) at /usr/src/mysql-5.6.28/storage/innobase/buf/buf0flu.cc:2375
#3 0x0000000000cfd758 in buf_flush_page_cleaner_thread (arg=0x0) at /usr/src/mysql-5.6.28/storage/innobase/buf/buf0flu.cc:2416
#4 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#5 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#6 0x0000000000000000 in ?? () Thread 9 (Thread 0x7f9c1790c940 (LWP 4392)):
#0 0x00007f9c7f897019 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000baaa63 in os_cond_wait (cond=0x194ece0, fast_mutex=0x194eca0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:214
#2 0x0000000000baaadf in os_event_wait_low (event=0x194eca0, reset_sig_count=1) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:592
#3 0x0000000000cf6f1d in buf_dump_thread (arg=0x0) at /usr/src/mysql-5.6.28/storage/innobase/buf/buf0dump.cc:594
#4 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#5 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#6 0x0000000000000000 in ?? () Thread 8 (Thread 0x7f9c0ffff940 (LWP 4393)):
#0 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000baa77b in os_cond_wait_timed (cond=0x476b760, fast_mutex=0x476b720, abstime=0x7f9c0ffff0e0) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:177
#2 0x0000000000baa9b0 in os_event_wait_time_low (event=0x476b720, time_in_usec=10000000, reset_sig_count=2) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:705
#3 0x0000000000d44dd2 in dict_stats_thread (arg=0x0) at /usr/src/mysql-5.6.28/storage/innobase/dict/dict0stats_bg.cc:348
#4 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#5 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#6 0x0000000000000000 in ?? () Thread 7 (Thread 0x7f9c1710b940 (LWP 4394)):
#0 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000baa77b in os_cond_wait_timed (cond=0x47b2460, fast_mutex=0x47b2420, abstime=0x7f9c1710b020) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:177
#2 0x0000000000baa9b0 in os_event_wait_time_low (event=0x47b2420, time_in_usec=5000000, reset_sig_count=1) at /usr/src/mysql-5.6.28/storage/innobase/os/os0sync.cc:705
#3 0x0000000000ca6df8 in ib_wqueue_timedwait (wq=0x47a7928, wait_in_usecs=5000000) at /usr/src/mysql-5.6.28/storage/innobase/ut/ut0wqueue.cc:154
#4 0x0000000000d8173e in fts_optimize_thread (arg=0x47a7928) at /usr/src/mysql-5.6.28/storage/innobase/fts/fts0opt.cc:3000
#5 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#6 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#7 0x0000000000000000 in ?? () Thread 6 (Thread 0x7f9c1690a940 (LWP 4395)):
#0 0x00007f9c7f89a9c8 in do_sigwait () from /lib64/libpthread.so.0
#1 0x00007f9c7f89aa6d in sigwait () from /lib64/libpthread.so.0
#2 0x0000000000603688 in signal_hand (arg=0x0) at /usr/src/mysql-5.6.28/sql/mysqld.cc:3190
#3 0x0000000000b11172 in pfs_spawn_thread (arg=0x47a1f70) at /usr/src/mysql-5.6.28/storage/perfschema/pfs.cc:1860
#4 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#5 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#6 0x0000000000000000 in ?? () Thread 5 (Thread 0x7f9c168c8940 (LWP 5335)):
#0 0x00007f9c7ed370b6 in poll () from /lib64/libc.so.6
#1 0x0000000000e7da67 in vio_io_wait (vio=0x4780e40, event=VIO_IO_EVENT_READ, timeout=28800000) at /usr/src/mysql-5.6.28/vio/viosocket.c:771
#2 0x0000000000e7c350 in vio_socket_io_wait (vio=0x4780e40, event=VIO_IO_EVENT_READ) at /usr/src/mysql-5.6.28/vio/viosocket.c:68
#3 0x0000000000e7c42b in vio_read (vio=0x4780e40, buf=0x4a04400 "\001", size=4) at /usr/src/mysql-5.6.28/vio/viosocket.c:123
#4 0x0000000000709e3e in net_read_raw_loop (net=0x48eda88, count=4) at /usr/src/mysql-5.6.28/sql/net_serv.cc:669
#5 0x0000000000709ff7 in net_read_packet_header (net=0x48eda88) at /usr/src/mysql-5.6.28/sql/net_serv.cc:751
#6 0x000000000070ade5 in net_read_packet (net=0x48eda88, complen=0x7f9c168c7f88) at /usr/src/mysql-5.6.28/sql/net_serv.cc:816
#7 0x000000000070af62 in my_net_read (net=0x48eda88) at /usr/src/mysql-5.6.28/sql/net_serv.cc:894
#8 0x00000000007d9a30 in do_command (thd=0x48ed830) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:970
#9 0x000000000078e3fb in do_handle_one_connection (thd_arg=0x48ed830) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:982
#10 0x000000000078e4c1 in handle_one_connection (arg=0x48ed830) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:898
#11 0x0000000000b11172 in pfs_spawn_thread (arg=0x47891a0) at /usr/src/mysql-5.6.28/storage/perfschema/pfs.cc:1860
#12 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#13 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#14 0x0000000000000000 in ?? () Thread 4 (Thread 0x7f9c16887940 (LWP 5367)):
#0 0x00007f9c7f897280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000abe163 in safe_cond_timedwait (cond=0x4945228, mp=0x49451b8, abstime=0x7f9c16882b20, file=0xf07240 "/usr/src/mysql-5.6.28/include/mysql/psi/mysql_thread.h", line=1199) at /usr/src/mysql-5.6.28/mysys/thr_mutex.c:278
#2 0x000000000070497e in inline_mysql_cond_timedwait (that=0x4945228, mutex=0x49451b8, abstime=0x7f9c16882b20, src_file=0xf070a8 "/usr/src/mysql-5.6.28/sql/mdl.cc", src_line=1327) at /usr/src/mysql-5.6.28/include/mysql/psi/mysql_thread.h:1199
#3 0x0000000000704a42 in MDL_wait::timed_wait (this=0x49451b8, owner=0x49450d0, abs_timeout=0x7f9c16882b20, set_status_on_timeout=false, wait_state_name=0x14f4b30 <MDL_key::m_namespace_to_wait_state_name+48>) at /usr/src/mysql-5.6.28/sql/mdl.cc:1326
#4 0x0000000000706a0d in MDL_context::acquire_lock (this=0x49451b8, mdl_request=0x7f9c16882be0, lock_wait_timeout=31536000) at /usr/src/mysql-5.6.28/sql/mdl.cc:2246
#5 0x0000000000706e99 in MDL_context::upgrade_shared_lock (this=0x49451b8, mdl_ticket=0x49c5c80, new_type=MDL_EXCLUSIVE, lock_wait_timeout=31536000) at /usr/src/mysql-5.6.28/sql/mdl.cc:2428
#6 0x000000000083e9a3 in mysql_inplace_alter_table (thd=0x49450d0, table_list=0x4989018, table=0x49c53a0, altered_table=0x49e2260, ha_alter_info=0x7f9c16883a20, inplace_supported=HA_ALTER_INPLACE_NO_LOCK_AFTER_PREPARE, target_mdl_request=0x7f9c16884380, alter_ctx=0x7f9c16882f70) at /usr/src/mysql-5.6.28/sql/sql_table.cc:6518
#7 0x0000000000840839 in mysql_alter_table (thd=0x49450d0, new_db=0x4989578 "test", new_name=0x0, create_info=0x7f9c16884e20, table_list=0x4989018, alter_info=0x7f9c16884f00, order_num=0, order=0x0, ignore=false) at /usr/src/mysql-5.6.28/sql/sql_table.cc:8454
#8 0x000000000099390d in Sql_cmd_alter_table::execute (this=0x49896f8, thd=0x49450d0) at /usr/src/mysql-5.6.28/sql/sql_alter.cc:313
#9 0x00000000007d5e0d in mysql_execute_command (thd=0x49450d0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:4976
#10 0x00000000007d67c4 in mysql_parse (thd=0x49450d0, rawbuf=0x4988ef0 "alter table t add column comment varchar(200) default \"123\"", length=59, parser_state=0x7f9c16886910) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:6386
#11 0x00000000007d83f4 in dispatch_command (command=COM_QUERY, thd=0x49450d0, packet=0x490d681 "alter table t add column comment varchar(200) default \"123\"", packet_length=59) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:1340
#12 0x00000000007d9c80 in do_command (thd=0x49450d0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:1037
#13 0x000000000078e3fb in do_handle_one_connection (thd_arg=0x49450d0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:982
#14 0x000000000078e4c1 in handle_one_connection (arg=0x49450d0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:898
#15 0x0000000000b11172 in pfs_spawn_thread (arg=0x4792af0) at /usr/src/mysql-5.6.28/storage/perfschema/pfs.cc:1860
#16 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#17 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#18 0x0000000000000000 in ?? () Thread 3 (Thread 0x7f9c16846940 (LWP 5408)):
#0 0x00007f9c7f897019 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000abdfb0 in safe_cond_wait (cond=0x17ecc60 <COND_thread_cache>, mp=0x17ea080 <LOCK_thread_count>, file=0xee0078 "/usr/src/mysql-5.6.28/include/mysql/psi/mysql_thread.h", line=1162) at /usr/src/mysql-5.6.28/mysys/thr_mutex.c:240
#2 0x0000000000600361 in inline_mysql_cond_wait (that=0x17ecc60 <COND_thread_cache>, mutex=0x17ea080 <LOCK_thread_count>, src_file=0xedef70 "/usr/src/mysql-5.6.28/sql/mysqld.cc", src_line=2687) at /usr/src/mysql-5.6.28/include/mysql/psi/mysql_thread.h:1162
#3 0x000000000060bced in block_until_new_connection () at /usr/src/mysql-5.6.28/sql/mysqld.cc:2687
#4 0x000000000060bfc2 in one_thread_per_connection_end (thd=0x49c02f0, block_pthread=true) at /usr/src/mysql-5.6.28/sql/mysqld.cc:2775
#5 0x000000000078e45e in do_handle_one_connection (thd_arg=0x49c02f0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:989
#6 0x000000000078e4c1 in handle_one_connection (arg=0x49c02f0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:898
#7 0x0000000000b11172 in pfs_spawn_thread (arg=0x47ac8d0) at /usr/src/mysql-5.6.28/storage/perfschema/pfs.cc:1860
#8 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#9 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#10 0x0000000000000000 in ?? () Thread 2 (Thread 0x7f9c16805940 (LWP 5684)):
#0 0x00007f9c7f897019 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000abdfb0 in safe_cond_wait (cond=0x17ecc60 <COND_thread_cache>, mp=0x17ea080 <LOCK_thread_count>, file=0xee0078 "/usr/src/mysql-5.6.28/include/mysql/psi/mysql_thread.h", line=1162) at /usr/src/mysql-5.6.28/mysys/thr_mutex.c:240
#2 0x0000000000600361 in inline_mysql_cond_wait (that=0x17ecc60 <COND_thread_cache>, mutex=0x17ea080 <LOCK_thread_count>, src_file=0xedef70 "/usr/src/mysql-5.6.28/sql/mysqld.cc", src_line=2687) at /usr/src/mysql-5.6.28/include/mysql/psi/mysql_thread.h:1162
#3 0x000000000060bced in block_until_new_connection () at /usr/src/mysql-5.6.28/sql/mysqld.cc:2687
#4 0x000000000060bfc2 in one_thread_per_connection_end (thd=0x4a108b0, block_pthread=true) at /usr/src/mysql-5.6.28/sql/mysqld.cc:2775
#5 0x000000000078e45e in do_handle_one_connection (thd_arg=0x4a108b0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:989
#6 0x000000000078e4c1 in handle_one_connection (arg=0x4a108b0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:898
#7 0x0000000000b11172 in pfs_spawn_thread (arg=0x478fe40) at /usr/src/mysql-5.6.28/storage/perfschema/pfs.cc:1860
#8 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#9 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#10 0x0000000000000000 in ?? () Thread 1 (Thread 0x7f9c7fcaa6f0 (LWP 4373)):
#0 0x00007f9c7ed370b6 in poll () from /lib64/libc.so.6
#1 0x00000000006047fd in handle_connections_sockets () at /usr/src/mysql-5.6.28/sql/mysqld.cc:6254
#2 0x000000000060b103 in mysqld_main (argc=8, argv=0x1841d80) at /usr/src/mysql-5.6.28/sql/mysqld.cc:5673
#3 0x00000000005fa9c3 in main (argc=4, argv=0x7fffab7fc558) at /usr/src/mysql-5.6.28/sql/main.cc:25
会话2:
函数调用顺序:
Thread 4 (Thread 0x7f9c16887940 (LWP 5367)):
pthread_cond_timedwait safe_cond_timedwait inline_mysql_cond_timedwait MDL_wait::timed_wait MDL_context::acquire_lock MDL_context::upgrade_shared_lock mysql_inplace_alter_table
//INPLACE：索引创建或者删除操作时不需要创建临时表 mysql_alter_table Sql_cmd_alter_table::execute mysql_execute_command mysql_parse dispatch_command do_command do_handle_one_connection handle_one_connection pfs_spawn_thread start_thread () clone
mysql> show variables like "old_alter_table"; //INPLACE
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| old_alter_table | OFF |
+-----------------+-------+
1 row in set (0.03 sec) mysql> select @@version;
+------------------+
| @@version |
+------------------+
| 5.6.28-debug-log |
+------------------+
1 row in set (0.00 sec)
实验2：
当：set global old_alter_table=on 创建临时表，重复实验1操作
会话3: Thread 2 (Thread 0x7f9c16805940 (LWP 5684)):
pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x0000000000abe163 in safe_cond_timedwait (cond=0x4945228, mp=0x49451b8, abstime=0x7f9c16800bb0, file=0xf07240 "/usr/src/mysql-5.6.28/include/mysql/psi/mysql_thread.h", line=1199) at /usr/src/mysql-5.6.28/mysys/thr_mutex.c:278
#2 0x000000000070497e in inline_mysql_cond_timedwait (that=0x4945228, mutex=0x49451b8, abstime=0x7f9c16800bb0, src_file=0xf070a8 "/usr/src/mysql-5.6.28/sql/mdl.cc", src_line=1327) at /usr/src/mysql-5.6.28/include/mysql/psi/mysql_thread.h:1199
#3 0x0000000000704a42 in MDL_wait::timed_wait (this=0x49451b8, owner=0x49450d0, abs_timeout=0x7f9c16800bb0, set_status_on_timeout=false, wait_state_name=0x14f4b30 <MDL_key::m_namespace_to_wait_state_name+48>) at /usr/src/mysql-5.6.28/sql/mdl.cc:1326
#4 0x0000000000706a0d in MDL_context::acquire_lock (this=0x49451b8, mdl_request=0x7f9c16800c70, lock_wait_timeout=31536000) at /usr/src/mysql-5.6.28/sql/mdl.cc:2246
#5 0x0000000000706e99 in MDL_context::upgrade_shared_lock (this=0x49451b8, mdl_ticket=0x4979de0, new_type=MDL_EXCLUSIVE, lock_wait_timeout=31536000) at /usr/src/mysql-5.6.28/sql/mdl.cc:2428
#6 0x000000000076117e in wait_while_table_is_used (thd=0x49450d0, table=0x49c53a0, function=HA_EXTRA_PREPARE_FOR_RENAME) at /usr/src/mysql-5.6.28/sql/sql_base.cc:2295
#7 0x0000000000841143 in mysql_alter_table (thd=0x49450d0, new_db=0x1932c28 "test", new_name=0x0, create_info=0x7f9c16802e20, table_list=0x19326c8, alter_info=0x7f9c16802f00, order_num=0, order=0x0, ignore=false) at /usr/src/mysql-5.6.28/sql/sql_table.cc:8656
#8 0x000000000099390d in Sql_cmd_alter_table::execute (this=0x1932da8, thd=0x49450d0) at /usr/src/mysql-5.6.28/sql/sql_alter.cc:313
#9 0x00000000007d5e0d in mysql_execute_command (thd=0x49450d0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:4976
#10 0x00000000007d67c4 in mysql_parse (thd=0x49450d0, rawbuf=0x19325a0 "alter table t add column comment varchar(200) default \"123\"", length=59, parser_state=0x7f9c16804910) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:6386
#11 0x00000000007d83f4 in dispatch_command (command=COM_QUERY, thd=0x49450d0, packet=0x48d2e21 "alter table t add column comment varchar(200) default \"123\"", packet_length=59) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:1340
#12 0x00000000007d9c80 in do_command (thd=0x49450d0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:1037
#13 0x000000000078e3fb in do_handle_one_connection (thd_arg=0x4a108b0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:982
#14 0x000000000078e4c1 in handle_one_connection (arg=0x4a108b0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:898
#15 0x0000000000b11172 in pfs_spawn_thread (arg=0x478fe40) at /usr/src/mysql-5.6.28/storage/perfschema/pfs.cc:1860
#16 0x00007f9c7f89283d in start_thread () from /lib64/libpthread.so.0
#17 0x00007f9c7ed3ffdd in clone () from /lib64/libc.so.6
#18 0x0000000000000000 in ?? ()
GDB调试MYSQL
会话0：
mysqld --datadir=/data --basedir=/usr/local/mysql56 --user=mysql --gdb //--gdb ctrl+c可中断到gdb命令行
会话2：
gdb -ex "set target-async 1" -ex "set pagination off" -ex "set non-stop on" attach mysqlpid
(gdb) info threads
Id Target Id Frame
22 Thread 0x7f1370ba2940 (LWP 8588) (running) ！！！！！！运行状态
21 Thread 0x7f13703a1940 (LWP 8589) (running)
20 Thread 0x7f136fba0940 (LWP 8590) (running)
19 Thread 0x7f136f39f940 (LWP 8591) (running)
18 Thread 0x7f136eb9e940 (LWP 8592) (running)
17 Thread 0x7f136e39d940 (LWP 8593) (running)
16 Thread 0x7f136db9c940 (LWP 8594) (running)
15 Thread 0x7f136d39b940 (LWP 8595) (running)
14 Thread 0x7f136cb9a940 (LWP 8596) (running)
13 Thread 0x7f136c399940 (LWP 8597) (running)
12 Thread 0x7f136b397940 (LWP 8599) (running)
11 Thread 0x7f136a275940 (LWP 8600) (running)
10 Thread 0x7f1369a74940 (LWP 8601) (running)
9 Thread 0x7f136bb98940 (LWP 8602) (running)
8 Thread 0x7f1369273940 (LWP 8603) (running)
7 Thread 0x7f1368a72940 (LWP 8604) (running)
6 Thread 0x7f1363fff940 (LWP 8605) (running)
5 Thread 0x7f13637fe940 (LWP 8606) (running)
4 Thread 0x7f1362ffd940 (LWP 8607) (running)
3 Thread 0x7f136ab96940 (LWP 8608) (running)
2 Thread 0x7f136ab55940 (LWP 8640) (running)
* 1 Thread 0x7f13d03bb6f0 (LWP 8587) 0x00007f13cf4480b6 in poll () from /lib64/libc.so.6 //主线程中断 thread apply 1 c
1.如果想要立即中断当前函数运行并返回，用return，当前函数的剩余语句将 不被执行。（return可带参数，可以此随意设定当前函数的返回值） 2.如果想让程序执行到当前函数返回之后停止，用finish，当前函数的剩余语句将
会正常运行。
会话1：
mysql> alter table t add column aaa varchar(200) default "123";
会话2：
b：
MDL_context::acquire_lock MDL_context::upgrade_shared_lock mysql_inplace_alter_table
//INPLACE：索引创建或者删除操作时不需要创建临时表 mysql_alter_table
会话3：
mysql> show processlist;
+----+------+-----------+------+---------+------+-------+----------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+-------+----------------------------------------------------------+
| 1 | root | localhost | test | Query | 14 | init | alter table t add column aaa varchar(200) default "123" |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+-------+----------------------------------------------------------+
2 rows in set (0.00 sec) mysql> show processlist;
+----+------+-----------+------+---------+------+----------------------+----------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+----------------------+----------------------------------------------------------+
| 1 | root | localhost | test | Query | 24 | checking permissions | alter table t add column aaa varchar(200) default "123" |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+----------------------+----------------------------------------------------------+
2 rows in set (0.00 sec) mysql> show processlist;
+----+------+-----------+------+---------+------+----------------+----------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+----------------+----------------------------------------------------------+
| 1 | root | localhost | test | Query | 31 | Opening tables | alter table t add column aaa varchar(200) default "123" |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+----------------+----------------------------------------------------------+
2 rows in set (0.00 sec) mysql> show processlist;
+----+------+-----------+------+---------+------+--------------+----------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+--------------+----------------------------------------------------------+
| 1 | root | localhost | test | Query | 553 | After create | alter table t add column aaa varchar(200) default "123" |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+--------------+----------------------------------------------------------+
2 rows in set (0.00 sec) mysql> show processlist;
+----+------+-----------+------+---------+------+----------------+----------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+----------------+----------------------------------------------------------+
| 1 | root | localhost | test | Query | 614 | altering table | alter table t add column aaa varchar(200) default "123" |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+----------------+----------------------------------------------------------+
2 rows in set (0.00 sec) mysql> show processlist;
+----+------+-----------+------+---------+------+------------------------------------------+----------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+------------------------------------------+----------------------------------------------------------+
| 1 | root | localhost | test | Query | 642 | committing alter table to storage engine | alter table t add column aaa varchar(200) default "123" |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+------------------------------------------+----------------------------------------------------------+
2 rows in set (0.00 sec) mysql> show processlist;
+----+------+-----------+------+---------+------+-------+----------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+-------+----------------------------------------------------------+
| 1 | root | localhost | test | Query | 675 | end | alter table t add column aaa varchar(200) default "123" |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+-------+----------------------------------------------------------+
2 rows in set (0.00 sec) mysql> show processlist;
+----+------+-----------+------+---------+------+-----------+----------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+-----------+----------------------------------------------------------+
| 1 | root | localhost | test | Query | 689 | query end | alter table t add column aaa varchar(200) default "123" |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+-----------+----------------------------------------------------------+
2 rows in set (0.00 sec) mysql> show processlist;
+----+------+-----------+------+---------+------+----------------+----------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+----------------+----------------------------------------------------------+
| 1 | root | localhost | test | Query | 715 | closing tables | alter table t add column aaa varchar(200) default "123" |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+----------------+----------------------------------------------------------+
2 rows in set (0.00 sec) mysql> show processlist;
+----+------+-----------+------+---------+------+---------------+----------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+---------------+----------------------------------------------------------+
| 1 | root | localhost | test | Query | 726 | freeing items | alter table t add column aaa varchar(200) default "123" |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+---------------+----------------------------------------------------------+
2 rows in set (0.00 sec) mysql> show processlist;
+----+------+-----------+------+---------+------+-------------+------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+-------------+------------------+
| 1 | root | localhost | test | Sleep | 733 | cleaning up | NULL |
| 4 | root | localhost | test | Query | 0 | init | show processlist |
+----+------+-----------+------+---------+------+-------------+------------------+
2 rows in set (0.00 sec)
MetaData Lock 杨奇龙 ---MYSQL博客专家的更多相关文章
- MYSQL 博客
DavidYang的博客 - CSDN.NET DimitriK's (dim) Weblog Xaprb · Stay Curious! 飞鸿无痕的博客 - ChinaUnix博客 何登成的技术博客 ...
- 数据库性能测试---前阿里数据库团队资深DBA杨奇龙
杨奇龙 前阿里数据库团队资深DBA 主要负责淘宝业务线,经历多次11.11,有海量业务访问DB架构设计经验. 目前就职于有赞科技DBA,负责数据库运维工作,熟悉MySQL 性能优化,故障诊断,性能压测 ...
- web前端/移动端H5博客专家博客大全--值得收藏的前端技术大牛博客地址
web前端/移动端H5博客专家博客大全--值得收藏的前端技术大牛博客地址 Huang Jie Blog .Com-前端开发 http://www.huangjieblog.com/?feed=rs ...
- 梦想还是要有的-纪念正式成为csdn博客专家暨年中总结
csdn博客:http://blog.csdn.net/tuzongxun 我的csdn历程(坚持总会有收获): 一年零三个月之前,2015年3月3日,我在csdn写下第一篇技术博客,只是记录了一 ...
- 如何成为CSDN博客专家
先看一下官方给出的要求: 申请CSDN博客专家应具备的条件: 1.原创IT类文章总数超过20篇,并且最近一个月内发布了新的原创IT类文章. 2.博客文章总的浏览量超过5万次以上. 3.文章内容的质量很 ...
- 今天我点亮了CSDN博客专家殊荣
很久以前,看着csdn博客学习第一篇博客时,我依旧记得,是一个名叫蒋老夫子的博客专家,文章写的非常认真.内心很崇拜.在想,若干年后,在哪个地方?以什么样的一种状态,也得到此殊荣,华为有句口号,叫勇敢做 ...
- CSDN博客专家申请成功
又一个值得纪念的日子,上周六申请CSDN博客专家,今天中午审批通过.使用CSDN好几年了,从未想到能把博客一步步的写到这个地步. 曾经,写过一段博客,只是为了记录和分享.中间由于工作的变动和繁忙中断了 ...
- 今天我成为了CSDN博客专家
刚刚收到了来自CSDN的回复,正如我的期待: 我随即回到自己的博客页面,欣喜地看到"专家"勋章被点亮了.Oh, yeah~ Q:我为什么要申请这个"专家"称号? ...
- 经过一段的努力，终于成为CSDN博客专家，感谢大家支持
感谢CSDN提供这么好的一个技术学习平台,通过各路大神的博客我成长了许多,同时也感谢支持我的朋友们,我会继续努力,用心去写好博客.还请继续关注我~ 谢谢!
随机推荐
- Latex 常用知识点存档
前言: 本篇仅作为自己的知识存档. $Latex$是什么,就不用介绍了,网上好多教程和知识点,当忘记的时候搜一下就可以了. 本科做美赛和毕设的时候用的$Latex$排版,最近开始在博客园写点东东,发现 ...
- MyEclipse过期激活方法
如果已经过期会提示,进行购买.重新激活和退出,我们选择重新激活. 打开浏览器,地址栏输入key.858game.com,然后输入名称,在线获得MyEclipse的激活码. 输入Sumscripter: ...
- BZOJ 1725: [Usaco2006 Nov]Corn Fields牧场的安排
Description Farmer John新买了一块长方形的牧场,这块牧场被划分成M列N行(1<=M<=12; 1<=N<=12),每一格都是一块正方形的土地.FJ打算在牧 ...
- 制作PPT时，可能这些小习惯你需要注意
- Server-Side Access Control
Firefox 3.5 implements the W3C Access Control specification. As a result, Firefox 3.5 sends specifi ...
- 我新买的红米手机，新浪和360浏览器都能进，也能看电视，就是不能上手机QQ和微信
1.请您在桌面下.点击手菜单键-全局搜索,输入网络助手,点击流量排行,点击批量联网控制,查看该软件下(不能上网的应用)wifi和流量2G/3G下方的选项是否都勾选的.如果没有勾选,请您勾选. 2:仍然 ...
- OA学习笔记-005-Spring2.5与struts2.1整合
一.单独测试strust 1.action package cn.itcast.oa.test; import org.springframework.context.annotation.Scope ...
- C++内存管理（超长，例子很详细，排版很好）
[导语] 内存管理是C++最令人切齿痛恨的问题,也是C++最有争议的问题,C++高手从中获得了更好的性能,更大的自由,C++菜鸟的收获则是一遍一遍的检查代码和对C++的痛恨,但内存管理在C++中无处不 ...
- Hibernate：组合模式解决树的映射
树经常用来展示目录结构,那么在Hibernate中怎样解决树的映射问题呢? 先来看一个分销商的树形结构的例子 所有分销商 东北区 辽宁省 沈阳医药 吉林省 华北区 北京市 北京医药 河北省 华南区 那 ...
- xmanager远程登录