一、數(shù)據(jù)表結構

CREATE TABLE `jx_attach` (

`attach_id` int(11) NOT NULL AUTO_INCREMENT,

`feed_id` int(11) DEFAULT NULL ,

`attach_name` varchar(255) NOT NULL,

`cycore_file_id` varchar(255) DEFAULT NULL ,

`attach_size` bigint(20) NOT NULL DEFAULT '0',

`complete` smallint(6) NOT NULL DEFAULT '0' ,

PRIMARY KEY (`attach_id`),

KEY `jx_trend_attach_FK` (`feed_id`) USING BTREE

) ENGINE=InnoDB AUTO_INCREMENT=394160 DEFAULT CHARSET=utf8;

二、現(xiàn)象

當多個連接同時對一個表的數(shù)據(jù)進行更新操作，那么速度將會越來越慢，持續(xù)一段時間后將出現(xiàn)數(shù)據(jù)表被鎖，從而影響到其它的查詢及更新。

存儲過程循環(huán)30次更新操作

/*30次更新操作*/

BEGIN

DECLARE v1 INT DEFAULT 30;

WHILE v1 > 0 DO

update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';

SET v1 = v1 - 1;

END WHILE;

END

執(zhí)行結果(速度非常慢)

時間: 29.876s

Procedure executed successfully

受影響的行: 0

200個數(shù)據(jù)更新操作，三個數(shù)據(jù)庫連接同時執(zhí)行

update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';

update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';

update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';

update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';

update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';

update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';

...等等

執(zhí)行結果(持續(xù)一段時間后速度越來越慢，出現(xiàn)等待鎖)

# Time: 151208 22:41:24

# User@Host: zmduan[zmduan] @ [192.168.235.1] Id: 2

# Query_time: 1.848644 Lock_time: 0.780778 Rows_sent: 0 Rows_examined: 393382

SET timestamp=1449643284;

update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';

.........

........

# User@Host: zmduan[zmduan] @ [192.168.235.1] Id: 2# Query_time:2.868598 Lock_time: 1.558542 Rows_sent: 0 Rows_examined: 393382

SET timestamp=1449643805;update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';[root@localhost log]# tail -f slow_query.log#User@Host: zmduan[zmduan] @ [192.168.235.1] Id: 19# Query_time:1.356797 Lock_time: 0.000169 Rows_sent: 1 Rows_examined: 393383

SET timestamp=1449643805;SELECT *

FROMjx_attach ja,jx_feed jfwhere ja.feed_id=jf.feed_id and ja.cycore_file_id='56677146da502cd8907eb5b7';

#User@Host: zmduan[zmduan] @ [192.168.235.1] Id: 2# Query_time:2.868598 Lock_time: 1.558542 Rows_sent: 0 Rows_examined: 393382

SET timestamp=1449643805;update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';

三、原因分析

MySQL的innodb存儲引擎支持行級鎖，innodb的行鎖是通過給索引項加鎖實現(xiàn)的，這就意味著只有通過索引條件檢索數(shù)據(jù)時，innodb才使用行鎖，否則使用表鎖。根據(jù)當前的數(shù)據(jù)更新語句(update jx_attach set complete=1,attach_size=63100 where cycore_file_id='56677142da502cd8907eb58f';)，該條件字段cycore_file_id并沒有添加索引，所以導致數(shù)據(jù)表被鎖。

四、解決辦法

為cycore_file_id添加索引

五、最終效果(30次更新操作)

時間: 0.094s

Procedure executed successfully

受影響的行: 0

總結

以上是生活随笔為你收集整理的mysql锁表更新_Mysql InnoDB 数据更新导致锁表的全部內(nèi)容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網(wǎng)站內(nèi)容還不錯，歡迎將生活随笔推薦給好友。