这里说的是innodb类型的死锁!
网上找了好多东西 各种命令查看死锁信息,后面这条能用:
show engine innodb status;(根据mysql版本而异)
这命令在mysql命令行执行后如果有死锁
会出现下面这一块:
------------------------
LATEST DETECTED DEADLOCK
------------------------
然后你可以根据这块内容找到你引起死锁的语句。
然后解决它,
我这次的死锁是因为,
有这么一条语句
update 表名 set xx=xxx where xxx=xxx!
其中xxx没有索引!
innodb是行级锁,但是mysql的机制是用索引来找到该行,如果你那个where字段没有索引,那么mysql就找不到那一行,就会锁整张表了
这样后面的访问就会引发死锁!
给xxx字段加上索引
解决问题。附上异常信息:
Caused by: org.springframework.dao.DeadlockLoserDataAccessException: SqlMapClient operation; SQL [];
--- The error occurred while applying a parameter map.
--- Check the point.updatePointAccount-InlineParameterMap.
--- Check the statement (update failed).
--- Cause: com.mysql.jdbc.exceptions.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction; nested exception is com.ibatis.common.jdbc.exception.NestedSQLException:
--- The error occurred while applying a parameter map.
--- Check the point.updatePointAccount-InlineParameterMap.
--- Check the statement (update failed).
--- Cause: com.mysql.jdbc.exceptions.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.translate(SQLErrorCodeSQLExceptionTranslator.java:300)
at org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:212)
at org.springframework.orm.ibatis.SqlMapClientTemplate.update(SqlMapClientTemplate.java:411)
at com.hsd.popularize.dao.BaseDaoImpl.update(BaseDaoImpl.java:162)
... 87 more
Caused by: com.ibatis.common.jdbc.exception.NestedSQLException:
--- The error occurred while applying a parameter map.
--- Check the point.updatePointAccount-InlineParameterMap.
--- Check the statement (update failed).
--- Cause: com.mysql.jdbc.exceptions.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeUpdate(GeneralStatement.java:91)
at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.update(SqlMapExecutorDelegate.java:505)
at com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.update(SqlMapSessionImpl.java:90)
at org.springframework.orm.ibatis.SqlMapClientTemplate$10.doInSqlMapClient(SqlMapClientTemplate.java:413)
at org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:209)
... 89 more
Caused by: com.mysql.jdbc.exceptions.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:941)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2870)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1573)
at com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1169)
at com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStatement.java:693)
at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:794)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.execute(NewProxyPreparedStatement.java:989)
at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.ibatis.common.jdbc.logging.PreparedStatementLogProxy.invoke(PreparedStatementLogProxy.java:62)
at com.sun.proxy.$Proxy20.execute(Unknown Source)
at com.ibatis.sqlmap.engine.execution.SqlExecutor.executeUpdate(SqlExecutor.java:81)
at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.sqlExecuteUpdate(GeneralStatement.java:200)
at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeUpdate(GeneralStatement.java:78)
... 93 more

MySQLstringtypesimpactstorageandperformanceasfollows:1)CHARisfixed-length,alwaysusingthesamestoragespace,whichcanbefasterbutlessspace-efficient.2)VARCHARisvariable-length,morespace-efficientbutpotentiallyslower.3)TEXTisforlargetext,storedoutsiderows,

MySQLstringtypesincludeVARCHAR,TEXT,CHAR,ENUM,andSET.1)VARCHARisversatileforvariable-lengthstringsuptoaspecifiedlimit.2)TEXTisidealforlargetextstoragewithoutadefinedlength.3)CHARisfixed-length,suitableforconsistentdatalikecodes.4)ENUMenforcesdatainte

MySQLoffersvariousstringdatatypes:1)CHARforfixed-lengthstrings,2)VARCHARforvariable-lengthtext,3)BINARYandVARBINARYforbinarydata,4)BLOBandTEXTforlargedata,and5)ENUMandSETforcontrolledinput.Eachtypehasspecificusesandperformancecharacteristics,sochoose

TograntpermissionstonewMySQLusers,followthesesteps:1)AccessMySQLasauserwithsufficientprivileges,2)CreateanewuserwiththeCREATEUSERcommand,3)UsetheGRANTcommandtospecifypermissionslikeSELECT,INSERT,UPDATE,orALLPRIVILEGESonspecificdatabasesortables,and4)

ToaddusersinMySQLeffectivelyandsecurely,followthesesteps:1)UsetheCREATEUSERstatementtoaddanewuser,specifyingthehostandastrongpassword.2)GrantnecessaryprivilegesusingtheGRANTstatement,adheringtotheprincipleofleastprivilege.3)Implementsecuritymeasuresl

ToaddanewuserwithcomplexpermissionsinMySQL,followthesesteps:1)CreatetheuserwithCREATEUSER'newuser'@'localhost'IDENTIFIEDBY'password';.2)Grantreadaccesstoalltablesin'mydatabase'withGRANTSELECTONmydatabase.TO'newuser'@'localhost';.3)Grantwriteaccessto'

The string data types in MySQL include CHAR, VARCHAR, BINARY, VARBINARY, BLOB, and TEXT. The collations determine the comparison and sorting of strings. 1.CHAR is suitable for fixed-length strings, VARCHAR is suitable for variable-length strings. 2.BINARY and VARBINARY are used for binary data, and BLOB and TEXT are used for large object data. 3. Sorting rules such as utf8mb4_unicode_ci ignores upper and lower case and is suitable for user names; utf8mb4_bin is case sensitive and is suitable for fields that require precise comparison.

The best MySQLVARCHAR column length selection should be based on data analysis, consider future growth, evaluate performance impacts, and character set requirements. 1) Analyze the data to determine typical lengths; 2) Reserve future expansion space; 3) Pay attention to the impact of large lengths on performance; 4) Consider the impact of character sets on storage. Through these steps, the efficiency and scalability of the database can be optimized.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

WebStorm Mac version
Useful JavaScript development tools

SublimeText3 English version
Recommended: Win version, supports code prompts!

Dreamweaver CS6
Visual web development tools

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

SublimeText3 Chinese version
Chinese version, very easy to use
