In this post, we will see possible reason and fixes for Com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Specified key was too long; max key length is 1000 byte exception in hibernate. This error message typically occurs when you are trying to create a MySQL index on a column with a key length that exceeds the maximum limit allowed for that column.
If we defined the entity and defined the id field as String then we might encounter this exception. For example below code will throw an exception.
@Entity
public class CarDTO {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private String id;
@Column(name = "model_id")
private String model;
@Column(name = "name")
private String name;
//getter & setter
}Fix – Change id type from String to Long.
The maximum index length in MySQL depends on the storage engine being used. For example, InnoDB has a maximum index length of 767 bytes, while MyISAM has a maximum index length of 1000 bytes. When you try to create an index on a column with a key length that exceeds the maximum limit for the storage engine being used, you will get this error message.
To resolve this issue, you can try one of the following solutions:
- Modify the column length: If the column’s data type is a string, you can reduce the length of the column to make the key length shorter.
- Change the table storage engine: You can change the storage engine for the table to InnoDB or another engine that has a larger maximum index length.
- Modify the index: You can modify the index to include fewer columns or shorter columns to reduce the key length.
- Use a prefix index: You can create an index that includes only the first few characters of the column values, using a prefix length that falls within the maximum index length limit.
By implementing one of the above solutions, you should be able to create the index without encountering the “Specified key was too long” error message.
Stacktrace for error.
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL via JDBC Statement
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlString(SchemaCreatorImpl.java:440) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlStrings(SchemaCreatorImpl.java:424) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.createFromMetadata(SchemaCreatorImpl.java:315) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.performCreation(SchemaCreatorImpl.java:166) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:135) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:121) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:155) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:72) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.internal.SessionFactoryImpl.(SessionFactoryImpl.java:312) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:462) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:892) [hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57) [spring-orm-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) [spring-orm-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:390) [spring-orm-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:377) [spring-orm-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) [spring-orm-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1765) [spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1702) [spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:579) [spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) [spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) [spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) [spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) [spring-beans-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1089) ~[spring-context-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:859) ~[spring-context-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.6.RELEASE.jar:5.0.6.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) ~[spring-boot-2.0.2.RELEASE.jar:2.0.2.RELEASE]
at com.requirednewexample.main.SpringMain.main(SpringMain.java:13) ~[classes/:na]
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Specified key was too long; max key length is 1000 bytes
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_251]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_251]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_251]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_251]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.mysql.jdbc.Util.getInstance(Util.java:408) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:944) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3976) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3912) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2530) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2683) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2482) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2440) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.mysql.jdbc.StatementImpl.executeInternal(StatementImpl.java:845) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:745) ~[mysql-connector-java-5.1.46.jar:5.1.46]
at com.zaxxer.hikari.pool.ProxyStatement.execute(ProxyStatement.java:95) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariProxyStatement.execute(HikariProxyStatement.java) ~[HikariCP-2.7.9.jar:na]
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
… 34 common frames omitted
That’s all about Com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Specified key was too long; max key length is 1000 byte.
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