问题描述
一般公司都有DBA，DBA极有可能开启了Safe mode，也就是不支持不带索引条件过滤的update操作。
而Spring Batch /Cloud Task就有一张表 JOB_SEQ或者 TASK_SEQ的表，只有一条数据，也无法完成update操作。
Could not increment ID for BATCH_JOB_SEQ sequence table; nested exception is java.sql.SQLException:
You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
解决方案
如果是DBA提供的数据库，那么无论怎么换数据库都无法解决。除非自己提供一个开发者自建的私库（不在DBA管理中的）。
更好的解决方案是，替换Spring JDBC的MySQLMaxValueIncrementer
这个类由 DefaultDataFieldMaxValueIncrementerFactory 创建：
//DefaultDataFieldMaxValueIncrementerFactory.java
@Override
public DataFieldMaxValueIncrementer getIncrementer(String incrementerType, String incrementerName) {
DatabaseType databaseType = DatabaseType.valueOf(incrementerType.toUpperCase());
if (databaseType == DB2 || databaseType == DB2AS400) {
return new DB2SequenceMaxValueIncrementer(dataSource, incrementerName);
}
else if (databaseType == DB2ZOS) {
return new DB2MainframeSequenceMaxValueIncrementer(dataSource, incrementerName);
}
else if (databaseType == DERBY) {
return new DerbyMaxValueIncrementer(dataSource, incrementerName, incrementerColumnName);
}
else if (databaseType == HSQL) {
return new HsqlMaxValueIncrementer(dataSource, incrementerName, incrementerColumnName);
}
else if (databaseType == H2) {
return new H2SequenceMaxValueIncrementer(dataSource, incrementerName);
}
else if (databaseType == MYSQL) {
MySQLMaxValueIncrementer mySQLMaxValueIncrementer = new MySQLMaxValueIncrementer(dataSource, incrementerName, incrementerColumnName);
mySQLMaxValueIncrementer.setUseNewConnection(true);
return mySQLMaxValueIncrementer;
}
....
}
那么就要替换这个DefaultDataFieldMaxValueIncrementerFactory，代码如下：
package io.github.slankka.springbatch.safemode.patch;
import org.springframework.batch.item.database.support.DefaultDataFieldMaxValueIncrementerFactory;
import org.springframework.batch.support.DatabaseType;
import org.springframework.jdbc.support.incrementer.DataFieldMaxValueIncrementer;
import javax.sql.DataSource;
/**
* project: springbatch safemode patch
* <br/>To prevent error: <br/>
* <code>
* Could not increment ID for BATCH_JOB_SEQ sequence table; <br/>
* nested exception is java.sql.SQLException: <br/>
* You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column <br/>
* </code>
*
* @author slankka on 2019/8/30.
*/
public class SafeModeMysqlIncreamentFactory extends DefaultDataFieldMaxValueIncrementerFactory {
private DataSource dataSource;
private String incrementerColumnName = "ID";
public SafeModeMysqlIncreamentFactory(DataSource dataSource) {
super(dataSource);
this.dataSource = dataSource;
}
@Override
public void setIncrementerColumnName(String incrementerColumnName) {
super.setIncrementerColumnName(incrementerColumnName);
this.incrementerColumnName = incrementerColumnName;
}
@Override
public DataFieldMaxValueIncrementer getIncrementer(String incrementerType, String incrementerName) {
DatabaseType databaseType = DatabaseType.valueOf(incrementerType.toUpperCase());
if (databaseType == DatabaseType.MYSQL) {
SafeModeMysqlMaxValueIncreamenter mySQLMaxValueIncrementer = new SafeModeMysqlMaxValueIncreamenter(dataSource, incrementerName, incrementerColumnName);
mySQLMaxValueIncrementer.setUseNewConnection(true);
return mySQLMaxValueIncrementer;
}
return super.getIncrementer(incrementerType, incrementerName);
}
}
这里提供了SafeModeMysqlMaxValueIncreamenter 类，这个类就是解决问题的关键：
直接复制MySQLMaxValueIncrementer的代码，修改 stmt.executeUpdate 的SQL语句，尾部追加 where columnName > 0。
这样就能骗过 SafeMode检查。另外，如果这个字段不是主键，把他设置为主键即可。
需要设置ID为主键的表有三个：
alter table batch_job_execution_seq ADD PRIMARY KEY('ID');
alter table batch_job_seq ADD PRIMARY KEY('ID');
alter table batch_step_execution_seq ADD PRIMARY KEY('ID');
@Override
protected synchronized long getNextKey() throws DataAccessException {
if (this.maxId == this.nextId) {
/*
* If useNewConnection is true, then we obtain a non-managed connection so our modifications
* are handled in a separate transaction. If it is false, then we use the current transaction's
* connection relying on the use of a non-transactional storage engine like MYISAM for the
* incrementer table. We also use straight JDBC code because we need to make sure that the insert
* and select are performed on the same connection (otherwise we can't be sure that last_insert_id()
* returned the correct value).
*/
Connection con = null;
Statement stmt = null;
boolean mustRestoreAutoCommit = false;
try {
if (this.useNewConnection) {
con = getDataSource().getConnection();
if (con.getAutoCommit()) {
mustRestoreAutoCommit = true;
con.setAutoCommit(false);
}
} else {
con = DataSourceUtils.getConnection(getDataSource());
}
stmt = con.createStatement();
if (!this.useNewConnection) {
DataSourceUtils.applyTransactionTimeout(stmt, getDataSource());
}
// Increment the sequence column...
String columnName = getColumnName();
try {
stmt.executeUpdate("update " + getIncrementerName() + " set " + columnName +
" = last_insert_id(" + columnName + " + " + getCacheSize() + ") where " + columnName + " > 0");
} catch (SQLException ex) {
throw new DataAccessResourceFailureException("Could not increment " + columnName + " for " +
getIncrementerName() + " sequence table", ex);
}
// Retrieve the new max of the sequence column...
ResultSet rs = stmt.executeQuery(VALUE_SQL);
try {
if (!rs.next()) {
throw new DataAccessResourceFailureException("last_insert_id() failed after executing an update");
}
this.maxId = rs.getLong(1);
} finally {
JdbcUtils.closeResultSet(rs);
}
this.nextId = this.maxId - getCacheSize() + 1;
} catch (SQLException ex) {
throw new DataAccessResourceFailureException("Could not obtain last_insert_id()", ex);
} finally {
JdbcUtils.closeStatement(stmt);
if (con != null) {
if (this.useNewConnection) {
try {
con.commit();
if (mustRestoreAutoCommit) {
con.setAutoCommit(true);
}
} catch (SQLException ignore) {
throw new DataAccessResourceFailureException(
"Unable to commit new sequence value changes for " + getIncrementerName());
}
JdbcUtils.closeConnection(con);
} else {
DataSourceUtils.releaseConnection(con, getDataSource());
}
}
}
} else {
this.nextId++;
}
return this.nextId;
}