Spring Global transaction vs Local transaction

Question

While reading through Spring transaction documentation I see that it supports both Global transactions and Local transactions.

• In simple terms what is global transaction and what is local transaction?
• What are the advantages of one over the other? What are the appropriate uses of them?

If I use the following configuration – does it mean it is a local transaction?

<tx:annotation-driven transaction-manager="transManager" />

<bean id="transManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="emf" />
</bean>

I tried searching both in Google and Stackoverflow, but did not get any resources explaining the same in simple terms.

Answer 1

Actually there are plenty of resources answering your first two questions, for example Spring Documentation explains what local and global transaction is and depicts their differences in chapter 9.2 Motivation. In few words:

Global Transaction is an application server managed transaction, allowing to work with different transactional resources (this might be two different database, database and message queue, etc)

Local Transaction is resource specific transaction (for example Oracle Transactions) and application server has nothing to do with them. (the same chapter explains the pros and cons of each of them very well and much better then I could explain, so I suggest you to give a closer look)

Answering your later question. The documentation says that JpaTransactionManager is capable for processing global transactions, so by looking at the piece of presented code it's hard to say if it's local or global transaction. The same documentation says that local single-resource transaction DataSourceTransactionManager should be used instead.