[java] Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect)

I have a java project that runs on a webserver. I always hit this exception.

I read some documentation and found that pessimistic locking (or optimistic, but I read that pessimistic is better) is the best way to prevent this exception.

But I couldn't find any clear example that explains how to use it.

My method is like:

    @Transactional
    public void test(Email email, String subject) {
        getEmailById(String id);
        email.setSubject(subject);
        updateEmail(email);
    }

while:

  • Email is a Hibernate class (it will be a table in the database)
  • getEmailById(String id) is a function that returns an email (this method is not annotated with @Transactional)
  • updateEmail(email): is a method that updates the email.

Note: I use Hibernate for save, update & so on (example: session.getcurrentSession.save(email))

The exception:

ERROR 2011-12-21 15:29:24,910 Could not synchronize database state with session [myScheduler-1]
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [email#21]
    at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:1792)
    at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2435)
    at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2335)
    at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2635)
    at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:115)
    at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:168)
    at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1027)
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:365)
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:137)
    at org.springframework.orm.hibernate3.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:656)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:754)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:723)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:393)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:120)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
    at $Proxy130.generateEmail(Unknown Source)
    at com.admtel.appserver.tasks.EmailSender.run(EmailNotificationSender.java:33)
    at com.admtel.appserver.tasks.EmailSender$$FastClassByCGLIB$$ea0d4fc2.invoke(<generated>)
    at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
    at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:688)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
    at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:55)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
    at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:50)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
    at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:50)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:621)
    at com.admtel.appserver.tasks.EmailNotificationSender$$EnhancerByCGLIB$$33eb7303.run(<generated>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:273)
    at org.springframework.scheduling.support.MethodInvokingRunnable.run(MethodInvokingRunnable.java:65)
    at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:51)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
    at java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:98)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:204)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:680)
ERROR 2011-12-21 15:29:24,915 [ exception thrown < EmailNotificationSender.run() > exception message Object of class [Email] with identifier [211]: optimistic locking failed; nested exception is org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [Email#21] with params ] [myScheduler-1]
org.springframework.orm.hibernate3.HibernateOptimisticLockingFailureException: Object of class [Email] with identifier [21]: optimistic locking failed; nested exception is 

The answer is


Pessimistic locking is generally not recommended and it's very costly in terms of performance on database side. The problem that you have mentioned (the code part) a few things are not clear such as:

  • If your code is being accessed by multiple threads at the same time.
  • How are you creating session object (not sure if you are using Spring)?

Hibernate Session objects are NOT thread-safe. So if there are multiple threads accessing the same session and trying to update the same database entity, your code can potentially end up in an error situation like this.

So what happens here is that more than one thread tries to update the same entity, one thread succeeds and when the next thread goes to commit the data, it sees that its already been modified and ends up throwing StaleObjectStateException.

EDIT:

There is a way to use Pessimistic Locking in Hibernate. Check out this link. But there seems to be some issue with this mechanism. I came across posting a bug in hibernate (HHH-5275), however. The scenario mentioned in the bug is as follows:

Two threads are reading the same database record; one of those threads should use pessimistic locking thereby blocking the other thread. But both threads can read the database record causing the test to fail.

This is very close to what you are facing. Please try this if this does not work, the only way I can think of is using Native SQL queries where you can achieve pessimistic locking in postgres database with SELECT FOR UPDATE query.


I know this is an old question, but some of us are still hitting it and look at the sky wondering how. Here is one kind of issue that I faced.

We have a queue manager that polls data and gives it to handlers for processing. To avoid picking up the same events again, the queue manager locks the record in the database with a LOCKED state.

    void poll() {
        record = dao.getLockedEntity();
        queue(record);
    }

this method wasn't transactional but dao.getLockedEntity() was transactional with REQUIRED.

All good and on the road, after few months in production, it failed with an optimistic locking exception.

After lots of debugging and checking in details we could find out that some one has changed the code like this:

    @Transactional(propagation=Propagation.REQUIRED, readOnly=false)
    void poll() {
        record = dao.getLockedEntity();
        queue(record);              
    }

So the record was queued even before the transaction in dao.getLockedEntity() gets committed (it uses the same transaction of poll method) and the object was changed underneath by the handlers (different threads) by the time the poll() method transaction gets committed.

We fixed the issue and it looks good now.

I thought of sharing it because optimistic lock exceptions can be confusing and are difficult to debug. Someone might get benefited from my experience.

Regards, Lyju


It doesn't appear that you are actually using the email that you retrieve from the database, but an older copy that you get as a parameter. Whatever is being used for version control on the row has changed between when the previous version was retrieved and when you are doing the update.

You probably want your code to look more like:

    @Transactional
    public void test(String id, String subject) {
       Email email = getEmailById(id);
       email.setSubject(subject);
       updateEmail(email);
    }

I had the this problem on my project.

After I implemented optimistic locking, I got the same exception. My mistake was that I did not remove the setter of the field that became the @Version. As the setter was being called in java space, the value of the field did not match the one generated by the DB anymore. So basically the version fields did not match anymore. At that point any modification on the entity resulted in:

org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect)

I am using H2 in memory DB and Hibernate.


This exception is probably caused by optimistic locking (or by a bug in your code). You're probably using it without knowing. And your pseudo-code (which should be replaced by real code to be able to diagnose the problem) is wrong. Hibernate saves all the modifications done to attached entities automatically. You shouldn't ever call update, merge or saveOrUpdate on an attached entity. Just do

Email email = session.get(emailId);
email.setSubject(subject);

No need to call update. Hibernate will flush the changes automatically before committing the transaction.


I had the same problem and in my case the problem was missing and/or incorrect equals implementation on some types of fields in the entity object. At commit time, Hibernate checks ALL entities loaded in the session to check if they are dirty. If any of the entities are dirty, hibernate tries to persist them - no matter of the fact that the actual object that is requested a save operation is not related to the other entities.

Entity dirtiness is done by comparing every property of given object (with their equals methods) or UserType.equals if property has an associated org.Hibernate.UserType.

Another thing that surprised me was, in my transaction (using Spring annotation @Transactional), I was dealing with a single entity. Hibernate was complaining about some random entity that's unrelated to that entity being saved. What I realized is there is an outermost transaction we create at REST controller level, so the scope of the session is too big and hence all objects ever loaded as part of request processing get checked for dirtiness.

Hope this helps someone, some day.

Thanks Rags


check if the object exists or not in DB, if it exists get the object and refresh it:

if (getEntityManager().contains(instance)) {
    getEntityManager().refresh(instance);
    return instance;
}

if it fails the above if condition... find the Object with Id in DB, do the operation which you need, in this case exactly changes will reflects.

if (....) {
    } else if (null != identity) {
        E dbInstance = (E) getEntityManager().find(instance.getClass(), identity);
        return dbInstance;
    }

I had the experienced the same issue in different context of my project and there are different scenarios like

 - object is accessed from various source like (server side and client)
 - without any interval accessing the same object from a different place

In the first case

When I issue a server cal, before save the that object their one call from js and trying to save and another place, I got like, js call is going two, three times(I thing that call binding thing cause the issue)

I solved by

e.preventDefault()

The second case,

object.lock()

I was also receiving such an exception, but the problem was in my Entity identifier. I am using UUID and there are some problems in the way Spring works with them. So I just added this line to my entity identifier and it began working:

@Column(columnDefinition = "BINARY(16)")

Here you can find a little bit more information.


I also ran into this error when attempting to update an existing row after creating a new one, and spent ages scratching my head, digging through transaction and version logic, until I realised that I had used the wrong type for one of my primary key columns.

I used LocalDate when I should have been using LocalDateTime – I think this was causing hibernate to not be able to distinguish entities, leading to this error.

After changing the key to be a LocalDateTime, the error went away. Also, updating individual rows began to work as well – previously it would fail to find a row for updating, and testing this separate issue was actually what led me to my conclusions regarding the primary key mapping.


Don't set an Id to the object you are saving as the Id will be autogenerated


This error occurred for me when I was trying to update the same row from 2 different sessions. I updated a field in one browser while a second was open and had already stored the original object in its session. When I attempted to update from this second "stale" session I get the stale object error. In order to correct this I refetch my object to be updated from the database before I set the value to be updated, then save it as normal.


Just in case someone checked this thread and had the same issue as mine...

Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect)

I'm using NHibernate, I receive same error, during creating an object...

I was passing the key manually, and also specified a GUID generator in mapping, so hibernate generate same exact error for me, so once I removed the GUID, and left the field empty, everything went just fine.

this answer may not help you, but will help someone like me, who just your thread becasue of same error


I had problems with the same error on more than one Spring project. For me a general solution was, to split my service Method, that each INSERT, UPDATE and DELETE action got an own Method with @Transactional. I think this problem relates to the internal Spring managment, where database interactions are executed at the end of the method and, in my oppinion, this is the point, where the Exception is triggered.


I had the same problem in my grails project. The Bug was, that i overwrite the getter method of a collection field. This returned always a new version of the collection in other thread.

class Entity {
    List collection

    List getCollection() {
        return collection.unique()
    }
}

The solution was to rename the getter method:

class Entity {
    List collection

    List getUniqueCollection() {
        return collection.unique()
    }
}

First check your imports, when you use session, transaction it should be org.hibernate and remove @Transactinal annotation. and most important in Entity class if you have used @GeneratedValue(strategy=GenerationType.AUTO) or any other then at the time of model object creation/entity object creation should not create id. final conclusion is if you want pass id filed i.e PK then remove @GeneratedValue from entity class.


In order to prevent StaleObjectStateException, in your hbm file write below code:

<timestamp name="lstUpdTstamp" column="LST_UPD_TSTAMP" source="db"/>

I had this problem in one of my apps, now, I know this is an old thread but here is my solution; I figured out by looking at the data inside the debugger that JVM actually didn't load it properly when Hibernate was trying to update the database (that is actually done in a different thread), so I added the keyword "volatile" to every field of the entities. It has some performance issues to do that but rather that than Heavy objects beeing thrown around...


Questions with java tag:

Under what circumstances can I call findViewById with an Options Menu / Action Bar item? How much should a function trust another function How to implement a simple scenario the OO way Two constructors How do I get some variable from another class in Java? this in equals method How to split a string in two and store it in a field How to do perspective fixing? String index out of range: 4 My eclipse won't open, i download the bundle pack it keeps saying error log getting " (1) no such column: _id10 " error Instantiating a generic type When to create variables (memory management) java doesn't run if structure inside of onclick listener String method cannot be found in a main class method Are all Spring Framework Java Configuration injection examples buggy? Calling another method java GUI I need to know how to get my program to output the word i typed in and also the new rearranged word using a 2D array Java and unlimited decimal places? Read input from a JOptionPane.showInputDialog box Cannot retrieve string(s) from preferences (settings) strange error in my Animation Drawable Two Page Login with Spring Security 3.2.x Hadoop MapReduce: Strange Result when Storing Previous Value in Memory in a Reduce Class (Java) Got a NumberFormatException while trying to parse a text file for objects Best way for storing Java application name and version properties Call japplet from jframe FragmentActivity to Fragment Comparing two joda DateTime instances Maven dependencies are failing with a 501 error IntelliJ: Error:java: error: release version 5 not supported Has been compiled by a more recent version of the Java Runtime (class file version 57.0) Why am I getting Unknown error in line 1 of pom.xml? Gradle: Could not determine java version from '11.0.2' Error: Java: invalid target release: 11 - IntelliJ IDEA Android Gradle 5.0 Update:Cause: org.jetbrains.plugins.gradle.tooling.util Why is 2 * (i * i) faster than 2 * i * i in Java? must declare a named package eclipse because this compilation unit is associated to the named module How do I install Java on Mac OSX allowing version switching? How to install JDK 11 under Ubuntu? Java 11 package javax.xml.bind does not exist IntelliJ can't recognize JavaFX 11 with OpenJDK 11 Difference between OpenJDK and Adoptium/AdoptOpenJDK OpenJDK8 for windows How to allow all Network connection types HTTP and HTTPS in Android (9) Pie? Find the smallest positive integer that does not occur in a given sequence Error: JavaFX runtime components are missing, and are required to run this application with JDK 11 How to uninstall Eclipse? Failed to resolve: com.google.firebase:firebase-core:16.0.1 How to resolve Unable to load authentication plugin 'caching_sha2_password' issue

Questions with hibernate tag:

Hibernate Error executing DDL via JDBC Statement How does spring.jpa.hibernate.ddl-auto property exactly work in Spring? Error creating bean with name 'entityManagerFactory' defined in class path resource : Invocation of init method failed JPA Hibernate Persistence exception [PersistenceUnit: default] Unable to build Hibernate SessionFactory Disable all Database related auto configuration in Spring Boot Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment] HikariCP - connection is not available Hibernate-sequence doesn't exist How to find distinct rows with field in list using JPA and Spring? Spring Data JPA and Exists query How to log SQL statements in Spring Boot? UnsatisfiedDependencyException: Error creating bean with name 'entityManagerFactory' How does the FetchMode work in Spring Data JPA Spring Data JPA map the native query result to Non-Entity POJO Native query with named parameter fails with "Not all named parameters have been set" Unable to get spring boot to automatically create database schema Default fetch type for one-to-one, many-to-one and one-to-many in Hibernate org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set Spring Hibernate - Could not obtain transaction-synchronized Session for current thread TransactionRequiredException Executing an update/delete query hibernate - get id after save object What is the use of the @Temporal annotation in Hibernate? Could not commit JPA transaction: Transaction marked as rollbackOnly Spring Boot + JPA : Column name annotation ignored Spring Boot - Handle to Hibernate SessionFactory No serializer found for class org.hibernate.proxy.pojo.javassist.Javassist? javax.validation.ValidationException: HV000183: Unable to load 'javax.el.ExpressionFactory' org.hibernate.NonUniqueResultException: query did not return a unique result: 2? What is the difference between Hibernate and Spring Data JPA org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'MyController': org.hibernate.MappingException: Unknown entity: annotations.Users Ignore fields from Java object dynamically while sending as JSON from Spring MVC org.hibernate.hql.internal.ast.QuerySyntaxException: table is not mapped How to fix Hibernate LazyInitializationException: failed to lazily initialize a collection of roles, could not initialize proxy - no Session spring data jpa @query and pageable JPA COUNT with composite primary key query not working How to resolve "could not execute statement; SQL [n/a]; constraint [numbering];"? How to fix org.hibernate.LazyInitializationException - could not initialize proxy - no Session org.hibernate.QueryException: could not resolve property: filename Difference between save and saveAndFlush in Spring data jpa Why do I need to configure the SQL dialect of a data source? Error creating bean with name 'entityManagerFactory how to fetch data from database in Hibernate what is the use of annotations @Id and @GeneratedValue(strategy = GenerationType.IDENTITY)? Why the generationtype is identity? [Ljava.lang.Object; cannot be cast to BeanFactory not initialized or already closed - call 'refresh' before could not extract ResultSet in hibernate Joining two table entities in Spring Data JPA Hibernate: best practice to pull all lazy collections UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only

Questions with spring tag:

Are all Spring Framework Java Configuration injection examples buggy? Two Page Login with Spring Security 3.2.x Access blocked by CORS policy: Response to preflight request doesn't pass access control check Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured ApplicationContextException: Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean Failed to auto-configure a DataSource: 'spring.datasource.url' is not specified Spring Data JPA findOne() change to Optional how to use this? After Spring Boot 2.0 migration: jdbcUrl is required with driverClassName The type WebMvcConfigurerAdapter is deprecated No converter found capable of converting from type to type No String-argument constructor/factory method to deserialize from String value ('') Java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/exc/InvalidDefinitionException Read file from resources folder in Spring Boot RestClientException: Could not extract response. no suitable HttpMessageConverter found The origin server did not find a current representation for the target resource or is not willing to disclose that one exists The origin server did not find a current representation for the target resource or is not willing to disclose that one exists. on deploying to tomcat Spring boot: Unable to start embedded Tomcat servlet container Spring Boot application in eclipse, the Tomcat connector configured to listen on port XXXX failed to start 'Field required a bean of type that could not be found.' error spring restful API using mongodb java.io.FileNotFoundException: class path resource cannot be opened because it does not exist Unsupported Media Type in postman Configure active profile in SpringBoot via Maven How does spring.jpa.hibernate.ddl-auto property exactly work in Spring? MultipartException: Current request is not a multipart request Consider defining a bean of type 'service' in your configuration [Spring boot] UnsatisfiedDependencyException: Error creating bean with name How Spring Security Filter Chain works Spring Boot Java Config Set Session Timeout What is the recommended project structure for spring boot rest projects? Spring @Autowired and @Qualifier Spring security CORS Filter 8080 port already taken issue when trying to redeploy project from Spring Tool Suite IDE how to use Spring Boot profiles Error creating bean with name 'entityManagerFactory' defined in class path resource : Invocation of init method failed Check date between two other dates spring data jpa How to beautifully update a JPA entity in Spring Data? How do I activate a Spring Boot profile when running from IntelliJ? Spring-boot default profile for integration tests Unable to find a @SpringBootConfiguration when doing a JpaTest Difference between the annotations @GetMapping and @RequestMapping(method = RequestMethod.GET) Spring Boot @Value Properties Where is the application.properties file in a Spring Boot project? How to return a html page from a restful controller in spring boot? How to set Spring profile from system variable? How to POST form data with Spring RestTemplate? Spring Data and Native Query with pagination Spring Resttemplate exception handling Spring Boot - Loading Initial Data Pass multiple parameters to rest API - Spring org.springframework.web.client.HttpClientErrorException: 400 Bad Request

Questions with amazon-web-services tag:

How to specify credentials when connecting to boto3 S3? Is there a way to list all resources in AWS Access denied; you need (at least one of) the SUPER privilege(s) for this operation Job for mysqld.service failed See "systemctl status mysqld.service" What is difference between Lightsail and EC2? AWS S3 CLI - Could not connect to the endpoint URL boto3 client NoRegionError: You must specify a region error only sometimes How to write a file or data to an S3 object using boto3 Missing Authentication Token while accessing API Gateway? The AWS Access Key Id does not exist in our records AccessDenied for ListObjects for S3 bucket when permissions are s3:* Listing files in a specific "folder" of a AWS S3 bucket Read file content from S3 bucket with boto3 AWS CLI S3 A client error (403) occurred when calling the HeadObject operation: Forbidden Retrieving subfolders names in S3 bucket from boto3 AWS Lambda import module error in python API Gateway CORS: no 'Access-Control-Allow-Origin' header Can't push image to Amazon ECR - fails with "no basic auth credentials" How can I resolve the error "The security token included in the request is invalid" when running aws iam upload-server-certificate? How to load npm modules in AWS Lambda? AWS : The config profile (MyName) could not be found How to choose an AWS profile when using boto3 to connect to CloudFront How to handle errors with boto3? Boto3 to download all files from a S3 Bucket Can an AWS Lambda function call another How to pass a querystring or route parameter to AWS Lambda from Amazon API Gateway AWS S3 - How to fix 'The request signature we calculated does not match the signature' error? Listing contents of a bucket with boto3 AWS EFS vs EBS vs S3 (differences & when to use?) How to save S3 object to a file using boto3 Error You must specify a region when running command aws ecs list-container-instances Amazon S3 exception: "The specified key does not exist" Why is this HTTP request not working on AWS Lambda? Downloading folders from aws s3, cp or sync? How do I install Python 3 on an AWS EC2 instance? How to yum install Node.JS on Amazon Linux Read file from aws s3 bucket using node fs URL for public Amazon S3 bucket The authorization mechanism you have provided is not supported. Please use AWS4-HMAC-SHA256 Difference between Amazon EC2 and AWS Elastic Beanstalk How To Set Up GUI On Amazon EC2 Ubuntu server Font from origin has been blocked from loading by Cross-Origin Resource Sharing policy AWS S3: The bucket you are attempting to access must be addressed using the specified endpoint AWS - Disconnected : No supported authentication methods available (server sent :publickey) Unable to load AWS credentials from the /AwsCredentials.properties file on the classpath Extension exists but uuid_generate_v4 fails Cannot ping AWS EC2 instance How do I get AWS_ACCESS_KEY_ID for Amazon? How to rename files and folder in Amazon S3? EC2 instance has no public DNS

Questions with pessimistic-locking tag:

Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) Optimistic vs. Pessimistic locking