Why MyBatis Returns -2147482646 with BATCH Executor and How to Fix It

Issue

When running a demo project the author noticed that MyBatis update and insert operations always returned the value -2147482646, regardless of the actual result.

Root Cause

The problem is caused by the defaultExecutorType being set to BATCH. In batch mode MyBatis discards the update count, and the BatchExecutor returns the constant -2147482646.

Fix

Change the executorType in the Spring configuration to SIMPLE (or remove the argument). Example bean definition:

<bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate">
    <constructor-arg name="sqlSessionFactory" ref="sqlSessionFactory"/>
    <!-- executor type -->
    <constructor-arg name="executorType" value="SIMPLE"/>
</bean>

After this change the update/insert methods return the correct affected‑row count.

Source Tracing

The author opened the MyBatis source code to follow the call chain:

Configuration loads conf.xml and builds a SqlSessionFactory. SqlSessionFactory.openSession() creates a SqlSession (interface with insert and update methods).

The default implementation is DefaultSqlSession, which delegates to an Executor.

If executorType is BATCH, the BatchExecutor is used; its update method returns the constant -2147482646.

When executorType is SIMPLE, SimpleExecutor calls Statement.getUpdateCount(), returning the actual number of rows affected.

Conclusion

Changing the executor type from BATCH to SIMPLE resolves the mysterious return value, and the article demonstrates the importance of tracing source code to understand unexpected framework behavior.