<p>I have trying to achieve row level locking in the postgres DB.Below is the sample code</p>

<p>Repository :</p>

<pre><code>@Repository
public interface DeploymentRepository extends JpaRepository&lt;Deployment,Long&gt; {
   @Lock(LockModeType.PESSIMISTIC_WRITE)
   List&lt;Deployment&gt; findByStatus(Status status);
 }
</code></pre>

<p>Scheduler function calling lockable method:</p>

<pre><code>@Scheduled(initialDelay = 1000, fixedRate = 10000)
public void checkStatus(){

    try {
        for (Deployment deployment : deploymentRepository.findByStatus(someStatus)) {

           //some method call

        }
    }catch (Exception e){
        logger.error("",e);

    }
}
</code></pre>

<p>I am running this on kubernetes with 3 replicas(3 instance of the scheduler is running).</p>

<p>My use case is the 
1. Data fetched by deploymentRepository.findByStatus(someStatus) in one instance should not fetch in other instance of scheduler until controller exists from for loop.</p>

<p>Error :</p>

<pre><code>org.springframework.dao.InvalidDataAccessApiUsageException: no transaction is in progress; nested exception is javax.persistence.TransactionRequiredException: no transaction is in progress
at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:402) ~[spring-orm-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:255) ~[spring-orm-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:527) ~[spring-orm-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:61) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:242) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:153) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:144) ~[spring-data-jpa-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$ExposeRepositoryInvocationInterceptor.invoke(CrudMethodMetadataPostProcessor.java:364) ~[spring-data-jpa-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at com.sun.proxy.$Proxy117.findByStatus(Unknown Source) ~[na:na]
at com.microfocus.resourcepoolmanagement.schedule.DeplyomentStatusUpdate.checkStatus(DeplyomentStatusUpdate.java:33) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_231]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_231]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_231]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_231]
at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84) [spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54) [spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_231]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [na:1.8.0_231]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_231]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [na:1.8.0_231]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_231]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_231]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_231]
Caused by: javax.persistence.TransactionRequiredException: no transaction is in progress
at org.hibernate.query.internal.AbstractProducedQuery.doList(AbstractProducedQuery.java:1532) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1505) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.query.Query.getResultList(Query.java:132) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at org.hibernate.query.criteria.internal.compile.CriteriaQueryTypeQueryAdapter.getResultList(CriteriaQueryTypeQueryAdapter.java:74) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_231]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_231]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_231]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_231]
at org.springframework.orm.jpa.SharedEntityManagerCreator$DeferredQueryInvocationHandler.invoke(SharedEntityManagerCreator.java:403) ~[spring-orm-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at com.sun.proxy.$Proxy134.getResultList(Unknown Source) ~[na:na]
at org.springframework.data.jpa.repository.query.JpaQueryExecution$CollectionExecution.doExecute(JpaQueryExecution.java:129) ~[spring-data-jpa-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:91) ~[spring-data-jpa-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:136) ~[spring-data-jpa-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:125) ~[spring-data-jpa-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:605) ~[spring-data-commons-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.lambda$invoke$3(RepositoryFactorySupport.java:595) ~[spring-data-commons-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:595) ~[spring-data-commons-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59) ~[spring-data-commons-2.1.10.RELEASE.jar:2.1.10.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:295) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.9.RELEASE.jar:5.1.9.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.1.9.RELEASE.jar:5.1.9.RELEASE]
... 25 common frames omitted
</code></pre>

<p>I was facing the same issue.</p>
<p>However, using <code>@Transactional</code> in the Service class method alone did not solve this problem. I used the <code>@Transactional</code> annotation in the Repository <code>findBy</code> method as well.</p>
<p>This ensured that both of them were running in the same transaction.</p>
