ALTER TABLE `question`

MODIFY COLUMN `title` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL COMMENT '修改字符集为utf8mb4，兼容表情符' AFTER `sid`,
MODIFY COLUMN `content` text CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL COMMENT '问题内容' AFTER `title`;

ALTER TABLE `answer`
MODIFY COLUMN `content` text CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL COMMENT '修改字符集为utf8mb4，兼容表情符' AFTER `qid`;

修改过程中锁表

 ‘

 修改 锁表

不能写，可读 

 sou456执行
show processlist; ： 7247418 sou456 116.204.67.22:64059 sou456 Query 0 starting show processlist

show processlist; 

Id User Host db Command Time State Info
3 root 127.0.0.1:61037 Sleep 6
59 replicator 11.192.74.135:62486 Binlog Dump GTID 716448 Master has sent all binlog to slave; waiting for more updates
63 event_scheduler localhost Daemon 716448 Waiting on empty queue
66 system user Connect 716448 Waiting for master to send event
67 system user Connect 0 Slave has read all relay log; waiting for more updates
68 system user Connect 716448 Waiting for an event from Coordinator
69 system user Connect 716448 Waiting for an event from Coordinator
70 system user Connect 716448 Waiting for an event from Coordinator
71 system user Connect 716448 Waiting for an event from Coordinator
72 system user Connect 716448 Waiting for an event from Coordinator
73 system user Connect 716448 Waiting for an event from Coordinator
74 system user Connect 716448 Waiting for an event from Coordinator
75 system user Connect 716448 Waiting for an event from Coordinator
6666579 sou456 116.204.67.22:62348 sou456 Sleep 1194
7205158 sou456 47.93.175.119:37612 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (12639882,'明教被围攻光明顶时，杨逍他
7205159 sou456 47.93.175.119:37614 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22570569,'你要注册哪里的公司，名称首
7205160 sou456 47.93.175.119:37620 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (8105944,'直线y=x将椭圆x^2+3y^2=6y分成两�
7205161 sou456 47.93.175.119:37624 sou456 Sleep 288
7205162 sou456 47.93.175.119:37628 sou456 Sleep 160
7205163 sou456 47.93.175.119:37630 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21245198,'\n\n体内有病毒，打疫苗已没�
7205164 sou456 47.93.175.119:37634 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21205223,'不需要 很标准。而且还没达�
7205165 sou456 47.93.175.119:37636 sou456 Query 36 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (19597350,'省内算是好点的 去年校考除�
7205166 sou456 47.93.175.119:37644 sou456 Query 24 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (10410136,'1÷（1200+1300）\n=1÷1120\n=120（�
7205167 sou456 47.93.175.119:37648 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (20306253,'需要除～这些茶垢都是一些金
7205168 sou456 47.93.175.119:37652 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (16579337,'zisedebing01 加我好友么么哒！�
7205169 sou456 47.93.175.119:37656 sou456 Query 30 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (19813119,'中国猎头第一网 云猎头网 云�
7205170 sou456 47.93.175.119:37660 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (14752370,'家里已有的太阳能热水器和电
7205171 sou456 47.93.175.119:37662 sou456 Query 30 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22389438,'就算能维权我也绝不可能对自
7205172 sou456 47.93.175.119:37668 sou456 Query 30 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21481917,'一切没有直照的，都有可能，
7205173 sou456 47.93.175.119:37672 sou456 Sleep 152
7205174 sou456 47.93.175.119:37676 sou456 Query 25 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (18807626,'把和你提供的手机号相关绑定
7205175 sou456 47.93.175.119:37680 sou456 Query 26 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22571707,'专卖店好，更靠谱，有时候店
7205176 sou456 47.93.175.119:37684 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21915487,'菜单---设置---禁止后台运行，
7205177 sou456 47.93.175.119:37688 sou456 Query 35 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22373473,'岁运并临，三刑逢冲，不论身
7205178 sou456 47.93.175.119:37692 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22439945,'海水珍珠，珍珠母贝只有内层
7205179 sou456 47.93.175.119:37696 sou456 Sleep 160
7205180 sou456 47.93.175.119:37702 sou456 Query 29 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (8355248,'那可不行，小心刷不上变砖。\
7205181 sou456 47.93.175.119:37706 sou456 Sleep 161
7205182 sou456 47.93.175.119:37710 sou456 Query 27 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (18675950,'目前还没有开通南昌到万安的
7205183 sou456 47.93.175.119:37714 sou456 Sleep 155
7205184 sou456 47.93.175.119:37718 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21708714,'\n\n公交线路：地铁1号线，全�
7205185 sou456 47.93.175.119:37724 sou456 Query 37 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22126040,'\n商道枭雄 txt全集小说附件已
7205186 sou456 47.93.175.119:37728 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (5040365,'12月开的发票1月份是可以报销�
7205187 sou456 47.93.175.119:37732 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (19769818,'杭州西湖十景，除了在湖中的
7205188 sou456 47.93.175.119:37736 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (20947211,'2款都是真品不过相对而言下�
7205189 sou456 47.93.175.119:37740 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (13972030,'好望角和锦绣中华一小时30元�
7205190 sou456 47.93.175.119:37744 sou456 Sleep 163
7205191 sou456 47.93.175.119:37746 sou456 Query 29 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (20714602,'做人要诚实，真想干这行，打
7205192 sou456 47.93.175.119:37748 sou456 Query 24 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (13722950,'技术兵好，有技术就比没技术
7205193 sou456 47.93.175.119:37756 sou456 Query 38 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (8298037,'也被称为针距,3.50mm/3.81mm/5.00mm/
7205194 sou456 47.93.175.119:37758 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22423891,'我现在就在金矿搞金矿技术工
7205195 sou456 47.93.175.119:37762 sou456 Sleep 155
7205196 sou456 47.93.175.119:37766 sou456 Query 25 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22802318,'\n\n驾车路线：全程约128.0公里
7205197 sou456 47.93.175.119:37772 sou456 Sleep 162
7205198 sou456 47.93.175.119:37776 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (17946519,'全自动制砖生产线的制砖工作
7205199 sou456 47.93.175.119:37780 sou456 Sleep 159
7205200 sou456 47.93.175.119:37782 sou456 Query 28 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (14329682,'有的，没有就电不到老鼠了，
7205201 sou456 47.93.175.119:37788 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (12291951,'太多了。去国产的公司吧。中
7205202 sou456 47.93.175.119:37790 sou456 Query 27 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (18539477,'选择闪送，重量不重的话，3�
7205203 sou456 47.93.175.119:37794 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (14984492,'玉髓本就很不值钱，几十元的
7205204 sou456 47.93.175.119:37800 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (15807360,'\n\nNaHSO4溶于水电解出Na+ H+和S
7205205 sou456 47.93.175.119:37804 sou456 Sleep 287
7205207 sou456 47.93.175.119:37812 sou456 Query 24 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (8407840,'是纯白的衣服吗？用蓝色的墨�
7205208 sou456 47.93.175.119:37816 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22168479,'展开全部\n\n\n壹拾万元叁仟叁
7205209 sou456 47.93.175.119:37818 sou456 Query 29 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (17201988,'\n\n不属于特殊工种，跟一般�
7205210 sou456 47.93.175.119:37824 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22454659,'到校报道之后吧，毕竟还要你
7205211 sou456 47.93.175.119:37826 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21916452,'你好，CEA是用来诊断癌症的一
7205212 sou456 47.93.175.119:37832 sou456 Query 24 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (19302052,'应该类似受精卵吧，如果孵化
7205213 sou456 47.93.175.119:37834 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22093736,'简介：淮北市中银佳信房地产
7205214 sou456 47.93.175.119:37838 sou456 Query 35 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (20807767,'装到脚架上，用快门线，手动
7205215 sou456 47.93.175.119:37842 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (20967190,'简介：注册号：****所在地：�
7205216 sou456 47.93.175.119:37848 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22691597,'测绘的行业资质管理在国土局
7205217 sou456 47.93.175.119:37850 sou456 Sleep 159
7205218 sou456 47.93.175.119:37856 sou456 Query 25 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22320865,'PC上安装MAC操作系统，硬件的�
7205219 sou456 47.93.175.119:37860 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21240597,'康熙粉彩。大概二万元左右。
7205220 sou456 47.93.175.119:37864 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21955440,'这里不可以放号码\n你可以去�
7205221 sou456 47.93.175.119:37868 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (20577875,'C.髋关节伸、膝关节伸、踝关�
7205222 sou456 47.93.175.119:37872 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22202868,'鱼肉所含的蛋白质是完全蛋白
7205223 sou456 47.93.175.119:37876 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (18872795,'你打算找什么样的工作呢 我�
7205224 sou456 47.93.175.119:37880 sou456 Sleep 288
7205225 sou456 47.93.175.119:37884 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22054651,'您好，感谢您对拉卡拉的关注
7205226 sou456 47.93.175.119:37888 sou456 Query 27 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (17575594,'100多人的工厂还没有厂规，那
7205227 sou456 47.93.175.119:37892 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (8263635,'树木增粗，树皮加厚，采用氯�
7205228 sou456 47.93.175.119:37894 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22344481,'你要是去集红堂，可以选择白
7205229 sou456 47.93.175.119:37900 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22760712,'很多前扣和测扣的都是很难开
7205230 sou456 47.93.175.119:37902 sou456 Query 23 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (18867043,'长相很重要的。道不是漂亮与
7205231 sou456 47.93.175.119:37908 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22635591,'ur commitment to eachothe',1545208893),
7205232 sou456 47.93.175.119:37912 sou456 Query 21 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22867652,'(3-4i)(3+4i)\n=9-16i^2\n=9+16\n=25',154
7205233 sou456 47.93.175.119:37916 sou456 Query 29 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22064566,'你好朋友,根据你的提问,考虑�
7205234 sou456 47.93.175.119:37920 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (14552279,'您好 您能提供给我一份吗？�
7205235 sou456 47.93.175.119:37924 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (14246988,'股市涨涨跌跌乃正常现象，保
7205236 sou456 47.93.175.119:37928 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22685629,'温控盒子装上雾化器之后不能
7205237 sou456 47.93.175.119:37932 sou456 Query 27 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21764462,'现在是吞咽困难吗？专业机构
7205238 sou456 47.93.175.119:37934 sou456 Query 29 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (20506921,'之所以说发酵是微生物的呼吸
7205239 sou456 47.93.175.119:37940 sou456 Query 30 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (17900816,'1，剪力图正负号：使截面顺�
7205240 sou456 47.93.175.119:37944 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (17534131,'最简单的办法是去他临近的楼
7205241 sou456 47.93.175.119:37948 sou456 Sleep 288
7205242 sou456 47.93.175.119:37952 sou456 Sleep 288
7205243 sou456 47.93.175.119:37954 sou456 Sleep 155
7205244 sou456 47.93.175.119:37958 sou456 Query 24 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22520720,'\n通辽市翰博一品有6楼以下的
7205245 sou456 47.93.175.119:37964 sou456 Query 31 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (19922361,'Ag(NH3)2OH用于鉴别还原性基团�
7205246 sou456 47.93.175.119:37968 sou456 Sleep 287
7205247 sou456 47.93.175.119:37972 sou456 Query 25 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (14232576,'不一定，最好到银行鉴定一下
7205248 sou456 47.93.175.119:37976 sou456 Query 23 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (16990773,'前男友住在哪里怎么了呢？？
7205249 sou456 47.93.175.119:37980 sou456 Query 22 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21137574,'脱发和睡眠有一定的关系\n和�
7205250 sou456 47.93.175.119:37984 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22272922,'买箱子还要去淘宝，外边贵吗
7205251 sou456 47.93.175.119:37988 sou456 Query 33 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22662557,'对孩子用心点，别把新都放在
7205252 sou456 47.93.175.119:37992 sou456 Query 36 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (20758030,'找个地接是很容易的事情好吧
7205253 sou456 47.93.175.119:37996 sou456 Query 29 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (22415330,'选中车牌后,一般7个工作日就�
7205254 sou456 47.93.175.119:38000 sou456 Query 32 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (21355345,'多吃蔬菜是关键，每顿能吃一
7205255 sou456 47.93.175.119:38004 sou456 Sleep 160
7205256 sou456 47.93.175.119:38008 sou456 Query 29 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (18947593,'\n公交线路：252路，全程约3.4�
7205257 sou456 47.93.175.119:38012 sou456 Query 27 Waiting for table metadata lock INSERT INTO answer (qid, content, created) VALUES (15760059,'这个给你参考：\n各国对工频�
7205279 aurora 11.192.74.172:52332 Sleep 16
7205394 sou456 39.107.154.222:52890 sou456 Query 121 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (12748646,'不好说 但是据说挺有钱赚',1545
7205606 sou456 39.107.154.222:56310 sou456 Query 121 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (20298954,'可以的，要什么尺寸直接切。'
7205666 sou456 39.107.154.222:57296 sou456 Query 120 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (22597748,'用代码过去吧，我就是这样的�
7205749 sou456 39.107.154.222:58752 sou456 Query 121 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (9300737,'以科技智能与材质的精细，使�
7205867 sou456 39.107.154.222:32932 sou456 Query 120 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (14375004,'酸是因为鸡肉在冰箱冷藏室放�
7205935 sou456 39.107.154.222:34150 sou456 Query 119 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (20167572,'这个还是听取医生的建议吧。'
7205943 sou456 39.107.154.222:34438 sou456 Query 121 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (15438223,'是真的，感觉不错，每天一个�
7206367 sou456 47.93.175.119:55246 sou456 Query 120 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (22606027,'成都\n大型高二45座\n296\n105\n7:0
7206473 sou456 47.93.175.119:56380 sou456 Query 121 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (21339575,'在11月12号，挺多老人哭了！',1
7206533 sou456 39.107.154.222:45856 sou456 Query 117 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (18618882,'战俘列车\n二次世界大战期间�
7206610 sou456 39.107.154.222:47142 sou456 Query 121 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (22751508,'一定要躲Q\n你的Q有延迟，不要
7206692 sou456 39.107.154.222:48408 sou456 Query 117 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (21665129,'宋江三打祝家庄、三请：刘备�
7207012 sou456 47.93.175.161:39394 sou456 Query 121 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (21196713,'直径:800CM=8M\ns=3.14*4*4=50.24\n\nL=3
7207110 sou456 47.93.175.161:40646 sou456 Query 121 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (18399900,'买一个熏眼睛的眼罩效果也挺�
7207210 sou456 47.93.175.161:41886 sou456 Query 121 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (15790011,'\n\n这还不感动那真是日了狗\n\
7207432 sou456 47.93.175.161:44912 sou456 Query 117 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (12925677,'新能源是环保水平较高的能源�
7207833 sou456 47.93.175.119:55904 sou456 Query 117 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (22723232,'\n\n给你也没用的，雷石歌库都
7207878 sou456 47.93.175.119:39636 sou456 Query 115 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (20444634,'个人认为15万买标致408比东风A9
7207949 sou456 47.93.175.119:54542 sou456 Query 116 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (21699789,'一、消费维权需要提交的证据\
7208184 sou456 116.204.67.22:65491 sou456 Query 117 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (16924307,'光明新区实行的是开发区管委�
7208433 sou456 116.204.67.22:49365 sou456 Query 118 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (21787659,'做传单，然后去发，在工厂区�
7208448 sou456 116.204.67.22:49372 sou456 Sleep 9743
7208474 sou456 116.204.67.22:49378 sou456 Query 121 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (5667631,'我个人反对这种“心脏记忆说�
7214452 sou456 116.204.67.22:50242 sou456 Query 117 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (21956149,'你是需要哪种呀?国标标准的还
7214457 sou456 116.204.67.22:50250 sou456 Query 122 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (16072952,'\n\n你好，我也需要这个音乐，
7214486 sou456 116.204.67.22:50260 sou456 Query 112 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (10374950,'不会了.\n只能涨不能跌了.\n国�
7214879 sou456 39.107.154.222:47854 sou456 Query 122 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (21826619,'一般三层结构的冰箱,中间零度
7215495 sou456 116.204.67.22:50694 sou456 Query 103 Waiting for table metadata lock INSERT INTO answer (qid, content,created) VALUES (11109623,'笔心为石墨合成的,笔杆为木头
7247418 sou456 116.204.67.22:64059 sou456 Query 0 starting show processlist
7257190 aurora 11.192.114.100:58448 Sleep 2821
7257191 aurora 11.218.166.161:48102 Sleep 2818
7257192 aurora 11.192.114.100:58454 Sleep 2818
7257196 aurora 11.192.114.100:58461 Sleep 2808
7257198 aurora 11.218.166.161:48112 information_schema Sleep 2811
7257200 aurora 11.218.166.161:48116 Sleep 2809
7257203 aurora 11.218.166.161:48120 Sleep 2808
7257204 aurora 11.218.166.161:48122 Sleep 2808
7257213 aurora 11.192.114.100:58480 Sleep 2629
7257217 aurora 11.218.166.161:48142 Sleep 2126
7257225 aurora 11.192.114.100:58500 Sleep 2793
7257663 sou456 116.204.67.22:63110 sou456 Sleep 2348
7257995 sou456 116.204.67.22:63846 sou456 Sleep 1929
7258698 sou456 116.204.67.22:49773 sou456 Sleep 1193
7258905 sou456 100.104.72.200:42153 sou456 Sleep 973
7259561 sou456 100.104.72.200:42899 sou456 Query 122 copy to tmp table ALTER TABLE `answer`
MODIFY COLUMN `content` text CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci

Waiting for table metadata lock

等待元数据锁

线下数据库测试

同线上阿里rds-mysql

alter table  原理

通过复制表到临时表，来实现表字段修改；

ALTER TABLE `answer`
MODIFY COLUMN `content` text CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL COMMENT '修改字符集为utf8mb4，兼容表情符' AFTER `qid`;

show processlist;

Id User Host db Command Time State Info
4 event_scheduler localhost Daemon 523672 Waiting on empty queue
4355 root DESKTOP-RVB6E5F:54581 sou456 Query 48 copy to tmp table ALTER TABLE `answer`
MODIFY COLUMN `content` text CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
4358 root DESKTOP-RVB6E5F:54678 Sleep 10
4359 root DESKTOP-RVB6E5F:54679 sou456 Sleep 10
4360 root DESKTOP-RVB6E5F:54681 sou456 Sleep 9
4361 root DESKTOP-RVB6E5F:54708 sou456 Query 0 starting show processlist

MySQL :: MySQL 5.7 Reference Manual :: 13.7.6.4 KILL Syntax https://dev.mysql.com/doc/refman/5.7/en/kill.html

KILL [CONNECTION | QUERY] processlist_id

SHOW PROCESSLIST;
SHOW PROCESSLIST WHERE Command="Query"; #不支持

select * from information_schema.processlist where Command="Query";

ID USER HOST DB COMMAND TIME STATE  INFO