Spring Batch JpaPagingItemReader: how to set a query hint? - oracle

Question

I need help because I can't understand how I can set a query hint in the JpaPagingItemReader.
This is the reader definition:
<bean id="itemReader" class="org.springframework.batch.item.database.JpaPagingItemReader" scope="step"
p:entityManagerFactory-ref="entityManagerFactoryOracle"
p:pageSize="${pageSize}"
p:queryString="SELECT t FROM test t">
</bean>
I need to set an Oracle hint in the queryString but I can't find the right way to specify it.
If I set the hint like this
SELECT /*+ INDEX(t indexName) */ t FROM test t
I got this exception:
2018-09-14 08:28:16.035 [SimpleAsyncTaskExecutor-1] ERROR [org.hibernate.hql.internal.ast.ErrorCounter][reportError] - line 1:8: unexpected token: /
line 1:8: unexpected token: /
at org.hibernate.hql.internal.antlr.HqlBaseParser.selectClause(HqlBaseParser.java:1245)
at org.hibernate.hql.internal.antlr.HqlBaseParser.selectFrom(HqlBaseParser.java:1022)
at org.hibernate.hql.internal.antlr.HqlBaseParser.queryRule(HqlBaseParser.java:730)
at org.hibernate.hql.internal.antlr.HqlBaseParser.selectStatement(HqlBaseParser.java:323)
at org.hibernate.hql.internal.antlr.HqlBaseParser.statement(HqlBaseParser.java:186)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:279)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:187)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:142)
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:115)
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:76)
at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:150)
at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:302)
at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:240)
at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1894)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:291)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:342)
at com.sun.proxy.$Proxy33.createQuery(Unknown Source)
at org.springframework.batch.item.database.JpaPagingItemReader.createQuery(JpaPagingItemReader.java:112)
at org.springframework.batch.item.database.JpaPagingItemReader.doReadPage(JpaPagingItemReader.java:203)
at org.springframework.batch.item.database.AbstractPagingItemReader.doRead(AbstractPagingItemReader.java:108)
at org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader.read(AbstractItemCountingItemStreamItemReader.java:88)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:133)
at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:121)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
at com.sun.proxy.$Proxy36.read(Unknown Source)
at org.springframework.batch.core.step.item.SimpleChunkProvider.doRead(SimpleChunkProvider.java:91)
at org.springframework.batch.core.step.item.SimpleChunkProvider.read(SimpleChunkProvider.java:157)
at org.springframework.batch.core.step.item.SimpleChunkProvider$1.doInIteration(SimpleChunkProvider.java:116)
at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:374)
at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215)
at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:144)
at org.springframework.batch.core.step.item.SimpleChunkProvider.provide(SimpleChunkProvider.java:110)
at org.springframework.batch.core.step.item.ChunkOrientedTasklet.execute(ChunkOrientedTasklet.java:69)
at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:406)
at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:330)
at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:133)
at org.springframework.batch.core.step.tasklet.TaskletStep$2.doInChunkContext(TaskletStep.java:271)
at org.springframework.batch.core.scope.context.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:81)
at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:374)
at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215)
at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:144)
at org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:257)
at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:200)
at org.springframework.batch.core.partition.support.TaskExecutorPartitionHandler$1.call(TaskExecutorPartitionHandler.java:139)
at org.springframework.batch.core.partition.support.TaskExecutorPartitionHandler$1.call(TaskExecutorPartitionHandler.java:136)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.lang.Thread.run(Thread.java:748)
Any idea?
Thanks a lot for your help.

Answer 1

If your JPA provider does not support hints to be defined inline in the queryString, you can configure the JpaPagingItemReader with a custom JpaQueryProvider instead of a queryString. This interface allows you to have control over the creation of the query that will be executed.
In your case, you can use the JpaNativeQueryProvider implementation which supports query hints. See its Javadoc.