{"id":1845,"date":"2020-07-01T06:23:59","date_gmt":"2020-06-30T22:23:59","guid":{"rendered":"http:\/\/39.97.231.10\/?p=1845"},"modified":"2020-07-01T06:23:59","modified_gmt":"2020-06-30T22:23:59","slug":"mysql-%e5%9b%9b%e7%a7%8d%e4%ba%8b%e5%8a%a1%e9%9a%94%e7%a6%bb%e7%ba%a7%e7%9a%84%e8%af%b4%e6%98%8e","status":"publish","type":"post","link":"http:\/\/www.weijing.co\/?p=1845","title":{"rendered":"MySQL \u56db\u79cd\u4e8b\u52a1\u9694\u79bb\u7ea7\u7684\u8bf4\u660e"},"content":{"rendered":"
\n
\n\u6309\u7167SQL:1992 \u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\uff0cInnoDB\u9ed8\u8ba4\u662f\u53ef\u91cd\u590d\u8bfb\u7684\uff08REPEATABLE READ\uff09\u3002MySQL\/InnoDB \u63d0\u4f9bSQL\u6807\u51c6\u6240\u63cf\u8ff0\u7684\u6240\u6709\u56db\u4e2a\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u3002\u4f60\u53ef\u4ee5\u5728\u547d\u4ee4\u884c\u7528–transaction-isolation\u9009\u9879\uff0c\u6216\u5728\u9009\u9879\u6587\u4ef6\u91cc\uff0c\u4e3a\u6240\u6709\u8fde\u63a5\u8bbe\u7f6e\u9ed8\u8ba4\u9694\u79bb\u7ea7\u522b\u3002
\n\u4f8b\u5982\uff0c\u4f60\u53ef\u4ee5\u5728my.inf\u6587\u4ef6\u7684[mysqld]\u8282\u91cc\u7c7b\u4f3c\u5982\u4e0b\u8bbe\u7f6e\u8be5\u9009\u9879\uff1a<\/p>\n
\n
transaction-isolation = {READ-UNCOMMITTED | READ-COMMITTED | REPEATABLE-READ | SERIALIZABLE}<\/pre>\n<\/div>\n
\u7528\u6237\u53ef\u4ee5\u7528SET TRANSACTION\u8bed\u53e5\u6539\u53d8\u5355\u4e2a\u4f1a\u8bdd\u6216\u8005\u6240\u6709\u65b0\u8fdb\u8fde\u63a5\u7684\u9694\u79bb\u7ea7\u522b\u3002\u5b83\u7684\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n
\n
SET [SESSION | GLOBAL] TRANSACTION ISOLATION LEVEL {READ UNCOMMITTED | READ COMMITTED | REPEATABLE READ | SERIALIZABLE}<\/pre>\n<\/div>\n
\u6ce8\u610f\uff1a\u9ed8\u8ba4\u7684\u884c\u4e3a\uff08\u4e0d\u5e26session\u548cglobal\uff09\u662f\u4e3a\u4e0b\u4e00\u4e2a\uff08\u672a\u5f00\u59cb\uff09\u4e8b\u52a1\u8bbe\u7f6e\u9694\u79bb\u7ea7\u522b\u3002\u5982\u679c\u4f60\u4f7f\u7528GLOBAL\u5173\u952e\u5b57\uff0c\u8bed\u53e5\u5728\u5168\u5c40\u5bf9\u4ece\u90a3\u70b9\u5f00\u59cb\u521b\u5efa\u7684\u6240\u6709\u65b0\u8fde\u63a5\uff08\u9664\u4e86\u4e0d\u5b58\u5728\u7684\u8fde\u63a5\uff09\u8bbe\u7f6e\u9ed8\u8ba4\u4e8b\u52a1\u7ea7\u522b\u3002\u4f60\u9700\u8981SUPER\u6743\u9650\u6765\u505a\u8fd9\u4e2a\u3002\u4f7f\u7528SESSION \u5173\u952e\u5b57\u4e3a\u5c06\u6765\u5728\u5f53\u524d\u8fde\u63a5\u4e0a\u6267\u884c\u7684\u4e8b\u52a1\u8bbe\u7f6e\u9ed8\u8ba4\u4e8b\u52a1\u7ea7\u522b\u3002 \u4efb\u4f55\u5ba2\u6237\u7aef\u90fd\u80fd\u81ea\u7531\u6539\u53d8\u4f1a\u8bdd\u9694\u79bb\u7ea7\u522b\uff08\u751a\u81f3\u5728\u4e8b\u52a1\u7684\u4e2d\u95f4\uff09\uff0c\u6216\u8005\u4e3a\u4e0b\u4e00\u4e2a\u4e8b\u52a1\u8bbe\u7f6e\u9694\u79bb\u7ea7\u522b\u3002
\n\u4f60\u53ef\u4ee5\u7528\u4e0b\u5217\u8bed\u53e5\u67e5\u8be2\u5168\u5c40\u548c\u4f1a\u8bdd\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\uff1a<\/p>\n
\n
SELECT @@global.tx_isolation;\nSELECT @@session.tx_isolation;\nSELECT @@tx_isolation;<\/pre>\n<\/div>\n
—-\u4ee5\u4e0a\u624b\u518c\u4e2d\u7684\u7406\u8bba\u77e5\u8bc6;
\n===========================================================================================
\n\u9694\u79bb\u7ea7\u522b\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u810f\u8bfb\uff08Dirty Read\uff09\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u4e0d\u53ef\u91cd\u590d\u8bfb\uff08NonRepeatable Read\uff09\u00a0\u00a0\u00a0\u00a0 \u5e7b\u8bfb\uff08Phantom Read\uff09
\n===========================================================================================
\n\u672a\u63d0\u4ea4\u8bfb\uff08Read uncommitted\uff09\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u53ef\u80fd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u53ef\u80fd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u53ef\u80fd
\n\u5df2\u63d0\u4ea4\u8bfb\uff08Read committed\uff09\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u4e0d\u53ef\u80fd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u53ef\u80fd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u53ef\u80fd
\n\u53ef\u91cd\u590d\u8bfb\uff08Repeatable read\uff09\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0 \u00a0 \u4e0d\u53ef\u80fd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u4e0d\u53ef\u80fd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u53ef\u80fd
\n\u53ef\u4e32\u884c\u5316\uff08Serializable \uff09\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u4e0d\u53ef\u80fd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u4e0d\u53ef\u80fd\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u4e0d\u53ef\u80fd
\n===========================================================================================
\n\u00b7\u672a\u63d0\u4ea4\u8bfb(Read Uncommitted)\uff1a\u5141\u8bb8\u810f\u8bfb\uff0c\u4e5f\u5c31\u662f\u53ef\u80fd\u8bfb\u53d6\u5230\u5176\u4ed6\u4f1a\u8bdd\u4e2d\u672a\u63d0\u4ea4\u4e8b\u52a1\u4fee\u6539\u7684\u6570\u636e
\n\u00b7\u63d0\u4ea4\u8bfb(Read Committed)\uff1a\u53ea\u80fd\u8bfb\u53d6\u5230\u5df2\u7ecf\u63d0\u4ea4\u7684\u6570\u636e\u3002Oracle\u7b49\u591a\u6570\u6570\u636e\u5e93\u9ed8\u8ba4\u90fd\u662f\u8be5\u7ea7\u522b (\u4e0d\u91cd\u590d\u8bfb)
\n\u00b7\u53ef\u91cd\u590d\u8bfb(Repeated Read)\uff1a\u53ef\u91cd\u590d\u8bfb\u3002\u5728\u540c\u4e00\u4e2a\u4e8b\u52a1\u5185\u7684\u67e5\u8be2\u90fd\u662f\u4e8b\u52a1\u5f00\u59cb\u65f6\u523b\u4e00\u81f4\u7684\uff0cInnoDB\u9ed8\u8ba4\u7ea7\u522b\u3002\u5728SQL\u6807\u51c6\u4e2d\uff0c\u8be5\u9694\u79bb\u7ea7\u522b\u6d88\u9664\u4e86\u4e0d\u53ef\u91cd\u590d\u8bfb\uff0c\u4f46\u662f\u8fd8\u5b58\u5728\u5e7b\u8c61\u8bfb
\n\u00b7\u4e32\u884c\u8bfb(Serializable)\uff1a\u5b8c\u5168\u4e32\u884c\u5316\u7684\u8bfb\uff0c\u6bcf\u6b21\u8bfb\u90fd\u9700\u8981\u83b7\u5f97\u8868\u7ea7\u5171\u4eab\u9501\uff0c\u8bfb\u5199\u76f8\u4e92\u90fd\u4f1a\u963b\u585e
\n~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\n\u7528\u4f8b\u5b50\u8bf4\u660e\u5404\u4e2a\u7ea7\u522b\u7684\u60c5\u51b5\uff1a
\n\u2460 \u810f\u8bfb:\u00a0\u810f\u8bfb\u5c31\u662f\u6307\u5f53\u4e00\u4e2a\u4e8b\u52a1\u6b63\u5728\u8bbf\u95ee\u6570\u636e\uff0c\u5e76\u4e14\u5bf9\u6570\u636e\u8fdb\u884c\u4e86\u4fee\u6539\uff0c\u800c\u8fd9\u79cd\u4fee\u6539\u8fd8\u6ca1\u6709\u63d0\u4ea4\u5230\u6570\u636e\u5e93\u4e2d\uff0c\u8fd9\u65f6\uff0c\u53e6\u5916\u4e00\u4e2a\u4e8b\u52a1\u4e5f\u8bbf\u95ee\u8fd9\u4e2a\u6570\u636e\uff0c\u7136\u540e\u4f7f\u7528\u4e86\u8fd9\u4e2a\u6570\u636e\u3002<\/p>\n
\n
<\/div>\n
session 1:\nmysql> select @@global.tx_isolation;\n+-----------------------+\n| @@global.tx_isolation |\n+-----------------------+\n| REPEATABLE-READ       |\n+-----------------------+\n1 row in set (0.00 sec)\nmysql> select @@session.tx_isolation;\n+-----------------------+\n| @@session.tx_isolation |\n+-----------------------+\n| REPEATABLE-READ       |\n+-----------------------+\n1 row in set (0.00 sec)\nmysql> start transaction;\nQuery OK, 0 rows affected (0.00 sec)\nmysql> insert into ttd values(1);\nQuery OK, 1 row affected (0.05 sec)\nmysql> select * from ttd;\n+------+\n| id   |\n+------+\n|    1 |\n+------+\n1 row in set (0.00 sec)\nsession 2:\nmysql> select @@session.tx_isolation;\n+------------------------+\n| @@session.tx_isolation |\n+------------------------+\n| REPEATABLE-READ        |\n+------------------------+\n1 row in set (0.00 sec)\nmysql> select @@global.tx_isolation;\n+-----------------------+\n| @@global.tx_isolation |\n+-----------------------+\n| REPEATABLE-READ   |        --------\u8be5\u9694\u79bb\u7ea7\u522b\u4e0b(\u9664\u4e86 read uncommitted)\n+-----------------------+\n1 row in set (0.00 sec)\nmysql> select * from ttd;\nEmpty set (0.00 sec)              --------\u4e0d\u4f1a\u51fa\u73b0\u810f\u8bfb\nmysql> set session transaction isolation level read uncommitted;\nQuery OK, 0 rows affected (0.00 sec)\nmysql> select @@session.tx_isolation;\n+------------------------+\n| @@session.tx_isolation |\n+------------------------+\n| READ-UNCOMMITTED       |   --------\u8be5\u9694\u79bb\u7ea7\u522b\u4e0b\n+------------------------+\n1 row in set (0.00 sec)\nmysql> select * from ttd;\n+------+\n| id   |\n+------+\n|    1 |                                       --------REPEATABLE-READ\u7ea7\u522b\u51fa\u73b0\u810f\u8bfb\n+------+\n1 row in set (0.00 sec)<\/pre>\n<\/div>\n
\u7ed3\u8bba:session 2 \u5728READ-UNCOMMITTED \u4e0b\u8bfb\u53d6\u5230session 1 \u4e2d\u672a\u63d0\u4ea4\u4e8b\u52a1\u4fee\u6539\u7684\u6570\u636e.
\n\u2461 \u4e0d\u53ef\u91cd\u590d\u8bfb:\u662f\u6307\u5728\u4e00\u4e2a\u4e8b\u52a1\u5185\uff0c\u591a\u6b21\u8bfb\u540c\u4e00\u6570\u636e\u3002\u5728\u8fd9\u4e2a\u4e8b\u52a1\u8fd8\u6ca1\u6709\u7ed3\u675f\u65f6\uff0c\u53e6\u5916\u4e00\u4e2a\u4e8b\u52a1\u4e5f\u8bbf\u95ee\u8be5\u540c\u4e00\u6570\u636e\u3002\u90a3\u4e48\uff0c\u5728\u7b2c\u4e00\u4e2a\u4e8b\u52a1\u4e2d\u7684\u4e24\u6b21\u8bfb\u6570\u636e\u4e4b\u95f4\uff0c\u7531\u4e8e\u7b2c\u4e8c\u4e2a\u4e8b\u52a1\u7684\u4fee\u6539\uff0c\u90a3\u4e48\u7b2c\u4e00\u4e2a\u4e8b\u52a1\u4e24\u6b21\u8bfb\u5230\u7684\u7684\u6570\u636e\u53ef\u80fd\u662f\u4e0d\u4e00\u6837\u7684\u3002\u8fd9\u6837\u5c31\u53d1\u751f\u4e86\u5728\u4e00\u4e2a\u4e8b\u52a1\u5185\u4e24\u6b21\u8bfb\u5230\u7684\u6570\u636e\u662f\u4e0d\u4e00\u6837\u7684\uff0c\u56e0\u6b64\u79f0\u4e3a\u662f\u4e0d\u53ef\u91cd\u590d\u8bfb\u3002<\/p>\n
\n
session 1:\nmysql> select @@session.tx_isolation;\n+------------------------+\n| @@session.tx_isolation |\n+------------------------+\n| READ-COMMITTED         |\n+------------------------+\n1 row in set (0.00 sec)\nmysql> start transaction;\nQuery OK, 0 rows affected (0.00 sec)\nmysql> select * from ttd;\n+------+\n| id   |\n+------+\n|    1 |\n+------+\n1 row in set (0.00 sec)\nsession 2 :\nmysql> select @@session.tx_isolation;\n+------------------------+\n| @@session.tx_isolation |\n+------------------------+\n| REPEATABLE-READ        |\n+------------------------+\n1 row in set (0.00 sec)\nmysql> start transaction;\nQuery OK, 0 rows affected (0.00 sec)\nmysql> select * from ttd;\n+------+\n| id   |\n+------+\n|    1 |\n+------+\n1 row in set (0.00 sec)\nmysql> insert into ttd values(2);  \/\u4e5f\u53ef\u4ee5\u66f4\u65b0\u6570\u636e\nQuery OK, 1 row affected (0.00 sec)\nmysql> select * from ttd;\n+------+\n| id   |\n+------+\n|    1 |\n|    2 |\n+------+\n2 rows in set (0.00 sec)\nmysql> commit;\nQuery OK, 0 rows affected (0.02 sec)\nsession 2 \u63d0\u4ea4\u540e,\u67e5\u770bsession 1 \u7684\u7ed3\u679c;\nsession 1:\nmysql> select * from ttd;\n+------+\n| id   |\n+------+\n|    1 |                             --------\u548c\u7b2c\u4e00\u6b21\u7684\u7ed3\u679c\u4e0d\u4e00\u6837,READ-COMMITTED \u7ea7\u522b\u51fa\u73b0\u4e86\u4e0d\u91cd\u590d\u8bfb\n|    2 |\n+------+\n2 rows in set (0.00 sec)<\/pre>\n
<\/div>\n<\/div>\n
\u2462 \u53ef\u91cd\u590d\u8bfb:<\/p>\n
\n
session 1:\nmysql> select @@session.tx_isolation;\n+------------------------+\n| @@session.tx_isolation |\n+------------------------+\n| REPEATABLE-READ        |\n+------------------------+\n1 row in set (0.00 sec)\nmysql> start transaction;\nQuery OK, 0 rows affected (0.00 sec)\nmysql> select * from ttd;\n+------+\n| id   |\n+------+\n|    1 |\n|    2 |\n+------+\n2 rows in set (0.00 sec)\nsession 2 :\nmysql> select @@session.tx_isolation;\n+------------------------+\n| @@session.tx_isolation |\n+------------------------+\n| REPEATABLE-READ        |\n+------------------------+\n1 row in set (0.00 sec)\nmysql> start transaction;\nQuery OK, 0 rows affected (0.00 sec)\nmysql> insert into ttd values(3);\nQuery OK, 1 row affected (0.00 sec)\nmysql> commit;\nQuery OK, 0 rows affected (0.03 sec)\nsession 2 \u63d0\u4ea4\u540e,\u67e5\u770bsession 1 \u7684\u7ed3\u679c;\nsession 1:\nmysql> select * from ttd;\n+------+\n| id   |\n+------+\n|    1 |                                      --------\u548c\u7b2c\u4e00\u6b21\u7684\u7ed3\u679c\u4e00\u6837,REPEATABLE-READ\u7ea7\u522b\u51fa\u73b0\u4e86\u91cd\u590d\u8bfb\n|    2 |\n+------+\n2 rows in set (0.00 sec)\n(commit session 1 \u4e4b\u540e \u518dselect * from ttd \u53ef\u4ee5\u770b\u5230session 2 \u63d2\u5165\u7684\u6570\u636e3)<\/pre>\n
\\\"\u590d\u5236\u4ee3\u7801\\\"<\/a><\/div>\n<\/div>\n
\u2463 \u5e7b\u8bfb:\u7b2c\u4e00\u4e2a\u4e8b\u52a1\u5bf9\u4e00\u4e2a\u8868\u4e2d\u7684\u6570\u636e\u8fdb\u884c\u4e86\u4fee\u6539\uff0c\u8fd9\u79cd\u4fee\u6539\u6d89\u53ca\u5230\u8868\u4e2d\u7684\u5168\u90e8\u6570\u636e\u884c\u3002\u540c\u65f6\uff0c\u7b2c\u4e8c\u4e2a\u4e8b\u52a1\u4e5f\u4fee\u6539\u8fd9\u4e2a\u8868\u4e2d\u7684\u6570\u636e\uff0c\u8fd9\u79cd\u4fee\u6539\u662f\u5411\u8868\u4e2d\u63d2\u5165\u4e00\u884c\u65b0\u6570\u636e\u3002\u90a3\u4e48\uff0c\u4ee5\u540e\u5c31\u4f1a\u53d1\u751f\u64cd\u4f5c\u7b2c\u4e00\u4e2a\u4e8b\u52a1\u7684\u7528\u6237\u53d1\u73b0\u8868\u4e2d\u8fd8\u6709\u6ca1\u6709\u4fee\u6539\u7684\u6570\u636e\u884c\uff0c\u5c31\u597d\u8c61\u53d1\u751f\u4e86\u5e7b\u89c9\u4e00\u6837\u3002<\/p>\n
\n
mysql>CREATE TABLE `t_bitfly` (\n`id` bigint(20) NOT NULL default \\'0\\',\n`value` varchar(32) default NULL,\nPRIMARY KEY (`id`)\n) ENGINE=InnoDB\nmysql> select @@global.tx_isolation, @@tx_isolation;\n+-----------------------+-----------------+\n| @@global.tx_isolation | @@tx_isolation  |\n+-----------------------+-----------------+\n| REPEATABLE-READ       | REPEATABLE-READ |\n+-----------------------+-----------------+\n\u5b9e\u9a8c\u4e00\uff1a\nt Session A                   Session B\n|\n| START TRANSACTION;          START TRANSACTION;\n|\n| SELECT * FROM t_bitfly;\n| empty set\n|                             INSERT INTO t_bitfly\n|                             VALUES (1, \\'a\\');\n|\n| SELECT * FROM t_bitfly;\n| empty set\n|                             COMMIT;\n|\n| SELECT * FROM t_bitfly;\n| empty set\n|\n| INSERT INTO t_bitfly VALUES (1, \\'a\\');\n| ERROR 1062 (23000):\n| Duplicate entry \\'1\\' for key 1\nv (shit, \u521a\u521a\u660e\u660e\u544a\u8bc9\u6211\u6ca1\u6709\u8fd9\u6761\u8bb0\u5f55\u7684)\n\u5982\u6b64\u5c31\u51fa\u73b0\u4e86\u5e7b\u8bfb\uff0c\u4ee5\u4e3a\u8868\u91cc\u6ca1\u6709\u6570\u636e\uff0c\u5176\u5b9e\u6570\u636e\u5df2\u7ecf\u5b58\u5728\u4e86\uff0c\u50bb\u4e4e\u4e4e\u7684\u63d0\u4ea4\u540e\uff0c\u624d\u53d1\u73b0\u6570\u636e\u51b2\u7a81\u4e86\u3002\n\u5b9e\u9a8c\u4e8c\uff1a\nt Session A                  Session B\n|\n| START TRANSACTION;         START TRANSACTION;\n|\n| SELECT * FROM t_bitfly;\n| +------+-------+\n| | id   | value |\n| +------+-------+\n| |    1 | a     |\n| +------+-------+\n|                            INSERT INTO t_bitfly\n|                            VALUES (2, \\'b\\');\n|\n| SELECT * FROM t_bitfly;\n| +------+-------+\n| | id   | value |\n| +------+-------+\n| |    1 | a     |\n| +------+-------+\n|                            COMMIT;\n|\n| SELECT * FROM t_bitfly;\n| +------+-------+\n| | id   | value |\n| +------+-------+\n| |    1 | a     |\n| +------+-------+\n|\n| UPDATE t_bitfly SET value=\\'z\\';\n| Rows matched: 2  Changed: 2  Warnings: 0\n| (\u600e\u4e48\u591a\u51fa\u6765\u4e00\u884c)\n|\n| SELECT * FROM t_bitfly;\n| +------+-------+\n| | id   | value |\n| +------+-------+\n| |    1 | z     |\n| |    2 | z     |\n| +------+-------+<\/pre>\n<\/div>\n
\u672c\u4e8b\u52a1\u4e2d\u7b2c\u4e00\u6b21\u8bfb\u53d6\u51fa\u4e00\u884c\uff0c\u505a\u4e86\u4e00\u6b21\u66f4\u65b0\u540e\uff0c\u53e6\u4e00\u4e2a\u4e8b\u52a1\u91cc\u63d0\u4ea4\u7684\u6570\u636e\u5c31\u51fa\u73b0\u4e86\u3002\u4e5f\u53ef\u4ee5\u770b\u505a\u662f\u4e00\u79cd\u5e7b\u8bfb\u3002
\n\u5f53\u9694\u79bb\u7ea7\u522b\u662f\u53ef\u91cd\u590d\u8bfb\uff0c\u4e14\u7981\u7528innodb_locks_unsafe_for_binlog\u7684\u60c5\u51b5\u4e0b\uff0c\u5728\u641c\u7d22\u548c\u626b\u63cfindex\u7684\u65f6\u5019\u4f7f\u7528\u7684next-key locks\u53ef\u4ee5\u907f\u514d\u5e7b\u8bfb\u3002
\n\u518d\u770b\u4e00\u4e2a\u5b9e\u9a8c\uff0c\u8981\u6ce8\u610f\uff0c\u8868t_bitfly\u91cc\u7684id\u4e3a\u4e3b\u952e\u5b57\u6bb5\u3002<\/p>\n
\n
\u5b9e\u9a8c\u4e09\uff1a\nt Session A                 Session B\n|\n| START TRANSACTION;        START TRANSACTION;\n|\n| SELECT * FROM t_bitfly\n| WHERE id<=1\n| FOR UPDATE;\n| +------+-------+\n| | id   | value |\n| +------+-------+\n| |    1 | a     |\n| +------+-------+\n|                           INSERT INTO t_bitfly\n|                           VALUES (2, \\'b\\');\n|                           Query OK, 1 row affected\n|\n| SELECT * FROM t_bitfly;\n| +------+-------+\n| | id   | value |\n| +------+-------+\n| |    1 | a     |\n| +------+-------+\n|                           INSERT INTO t_bitfly\n|                           VALUES (0, \\'0\\');\n|                           (waiting for lock ...then timeout)\n|                           ERROR 1205 (HY000):\n|                           Lock wait timeout exceeded;\n|                           try restarting transaction\n|\n| SELECT * FROM t_bitfly;\n| +------+-------+\n| | id   | value |\n| +------+-------+\n| |    1 | a     |\n| +------+-------+\n|                           COMMIT;\n|\n| SELECT * FROM t_bitfly;\n| +------+-------+\n| | id   | value |\n| +------+-------+\n| |    1 | a     |\n| +------+-------+<\/pre>\n<\/div>\n
\u53ef\u4ee5\u770b\u5230\uff0c\u7528id<=1\u52a0\u7684\u9501\uff0c\u53ea\u9501\u4f4f\u4e86id<=1\u7684\u8303\u56f4\uff0c\u53ef\u4ee5\u6210\u529f\u6dfb\u52a0id\u4e3a2\u7684\u8bb0\u5f55\uff0c\u6dfb\u52a0id\u4e3a0\u7684\u8bb0\u5f55\u65f6\u5c31\u4f1a\u7b49\u5f85\u9501\u7684\u91ca\u653e\u3002<\/p>\n
\n
<\/div>\n
\u5b9e\u9a8c\u56db\uff1a\u4e00\u81f4\u6027\u8bfb\u548c\u63d0\u4ea4\u8bfb\nt Session A                      Session B\n|\n| START TRANSACTION;             START TRANSACTION;\n|\n| SELECT * FROM t_bitfly;\n| +----+-------+\n| | id | value |\n| +----+-------+\n| |  1 | a     |\n| +----+-------+\n|                                INSERT INTO t_bitfly\n|                                VALUES (2, \\'b\\');\n|                                COMMIT;\n|\n| SELECT * FROM t_bitfly;\n| +----+-------+\n| | id | value |\n| +----+-------+\n| |  1 | a     |\n| +----+-------+\n|\n| SELECT * FROM t_bitfly LOCK IN SHARE MODE;\n| +----+-------+\n| | id | value |\n| +----+-------+\n| |  1 | a     |\n| |  2 | b     |\n| +----+-------+\n|\n| SELECT * FROM t_bitfly FOR UPDATE;\n| +----+-------+\n| | id | value |\n| +----+-------+\n| |  1 | a     |\n| |  2 | b     |\n| +----+-------+\n|\n| SELECT * FROM t_bitfly;\n| +----+-------+\n| | id | value |\n| +----+-------+\n| |  1 | a     |\n| +----+-------+<\/pre>\n
<\/div>\n<\/div>\n
\u5982\u679c\u4f7f\u7528\u666e\u901a\u7684\u8bfb\uff0c\u4f1a\u5f97\u5230\u4e00\u81f4\u6027\u7684\u7ed3\u679c\uff0c\u5982\u679c\u4f7f\u7528\u4e86\u52a0\u9501\u7684\u8bfb\uff0c\u5c31\u4f1a\u8bfb\u5230\u201c\u6700\u65b0\u7684\u201d\u201c\u63d0\u4ea4\u201d\u8bfb\u7684\u7ed3\u679c\u3002
\n\u672c\u8eab\uff0c\u53ef\u91cd\u590d\u8bfb\u548c\u63d0\u4ea4\u8bfb\u662f\u77db\u76fe\u7684\u3002\u5728\u540c\u4e00\u4e2a\u4e8b\u52a1\u91cc\uff0c\u5982\u679c\u4fdd\u8bc1\u4e86\u53ef\u91cd\u590d\u8bfb\uff0c\u5c31\u4f1a\u770b\u4e0d\u5230\u5176\u4ed6\u4e8b\u52a1\u7684\u63d0\u4ea4\uff0c\u8fdd\u80cc\u4e86\u63d0\u4ea4\u8bfb\uff1b\u5982\u679c\u4fdd\u8bc1\u4e86\u63d0\u4ea4\u8bfb\uff0c\u5c31\u4f1a\u5bfc\u81f4\u524d\u540e\u4e24\u6b21\u8bfb\u5230\u7684\u7ed3\u679c\u4e0d\u4e00\u81f4\uff0c\u8fdd\u80cc\u4e86\u53ef\u91cd\u590d\u8bfb\u3002
\n\u53ef\u4ee5\u8fd9\u4e48\u8bb2\uff0cInnoDB\u63d0\u4f9b\u4e86\u8fd9\u6837\u7684\u673a\u5236\uff0c\u5728\u9ed8\u8ba4\u7684\u53ef\u91cd\u590d\u8bfb\u7684\u9694\u79bb\u7ea7\u522b\u91cc\uff0c\u53ef\u4ee5\u4f7f\u7528\u52a0\u9501\u8bfb\u53bb\u67e5\u8be2\u6700\u65b0\u7684\u6570\u636e\uff08\u63d0\u4ea4\u8bfb\uff09\u3002
\nMySQL InnoDB\u7684\u53ef\u91cd\u590d\u8bfb\u5e76\u4e0d\u4fdd\u8bc1\u907f\u514d\u5e7b\u8bfb\uff0c\u9700\u8981\u5e94\u7528\u4f7f\u7528\u52a0\u9501\u8bfb\u6765\u4fdd\u8bc1\u3002\u800c\u8fd9\u4e2a\u52a0\u9501\u5ea6\u4f7f\u7528\u5230\u7684\u673a\u5236\u5c31\u662fnext-key locks<\/a>\u3002
\n\u603b\u7ed3:
\n\u56db\u4e2a\u7ea7\u522b\u9010\u6e10\u589e\u5f3a\uff0c\u6bcf\u4e2a\u7ea7\u522b\u89e3\u51b3\u4e00\u4e2a\u95ee\u9898\u3002\u4e8b\u52a1\u7ea7\u522b\u8d8a\u9ad8,\u6027\u80fd\u8d8a\u5dee,\u5927\u591a\u6570\u73af\u5883read committed \u53ef\u4ee5\u7528.\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
\u6309\u7167SQL:1992 \u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\uff0cInnoDB\u9ed8\u8ba4\u662f\u53ef\u91cd\u590d\u8bfb\u7684\uff08REPEATABLE READ\uff09\u3002MySQL …<\/p>\n
  MySQL \u56db\u79cd\u4e8b\u52a1\u9694\u79bb\u7ea7\u7684\u8bf4\u660e<\/span> \u67e5\u770b\u5168\u6587 »<\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":""},"categories":[90,88],"tags":[],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"mailpoet_newsletter_max":false,"woocommerce_thumbnail":false,"woocommerce_single":false,"woocommerce_gallery_thumbnail":false,"shop_catalog":false,"shop_single":false,"shop_thumbnail":false},"uagb_author_info":{"display_name":"weijing","author_link":"http:\/\/www.weijing.co\/?author=4"},"uagb_comment_info":0,"uagb_excerpt":"\u6309\u7167SQL:1992 \u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\uff0cInnoDB\u9ed8\u8ba4\u662f\u53ef\u91cd\u590d\u8bfb\u7684\uff08REPEATABLE READ\uff09\u3002MySQL…","_links":{"self":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts\/1845"}],"collection":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1845"}],"version-history":[{"count":0,"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts\/1845\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1845"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1845"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1845"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}