optimistic-locking

问题 How to use optimistic locking with batch updates? I am using SimpleJdbcTemplate and for a single row I can build update sql that increments version column value and includes version in WHERE clause. Unfortunately the result int[] updated = simpleJdbcTemplate.batchUpdate does not contain rowcounts when using oracle driver. All elements are -2 indicating unknown rowcount. Is there some other, more performant way of doing this than executing all updates individually? These batches contain an

问题 I am learning hibernate optimistic lock mechanism and I haven't found answer on my question in user guide Let's say we have entity like this: @Entity class Employee{ @Version Long versionField; List<Employee> subordinates; ... } And somewhere we have following code: Employee sub = .... Emplyee emp = readEmploye(); emp.getSubordinates().add(sub); Can I control of version incrementation at this case ? 回答1: By default no. Since you're not changing the entity, but rather other entities that are

问题 I am learning hibernate optimistic lock mechanism and I haven't found answer on my question in user guide Let's say we have entity like this: @Entity class Employee{ @Version Long versionField; List<Employee> subordinates; ... } And somewhere we have following code: Employee sub = .... Emplyee emp = readEmploye(); emp.getSubordinates().add(sub); Can I control of version incrementation at this case ? 回答1: By default no. Since you're not changing the entity, but rather other entities that are

问题 I have started using spring from last few months and I have a question on transactions. I have a java method inside my spring batch job which first does a select operation to get first 100 rows with status as 'NOT COMPLETED' and does a update on the selected rows to change the status to 'IN PROGRESS'. Since I'm processing around 10 million records, I want to run multiple instances of my batch job and each instance has multiple threads. For a single instance, to make sure two threads are not

问题 I just discovered that my application behaves differently when I use optimistic locking with a Postgresql or a MariaDB database and I am wondering if somebody can explain what happens and how could I make the application work in the same way with MariaDB? I use Postgresl 10.5 and MariaDB 10.3.10 with InnoDB engine and default settings. I use Spring framework version 5.1.0 and Hibernate 5.3.6. So my code looks like this: @Entity @Getter @Setter @NoArgsConstructor public class Bla { @Id

问题 I have two hibernate/JPA entities @Entity @Table(name = "conference_room", uniqueConstraints = @UniqueConstraint(columnNames = "code")) class ConferenceRoom { @Id @GeneratedValue(strategy = IDENTITY) @Column(name = "id", unique = true, nullable = false) private Integer id; @Column(name = "code", unique = true, length = 20) private String code; @OneToMany(fetch = FetchType.LAZY, mappedBy = "conferenceRoom") @Cascade({CascadeType.ALL}) private Set<Person> people = new HashSet<Person>(); //

问题 The question I have today is how to retry a method after the @Transactional annotation causes an Optimistic Lock Exception (OLE) and rolls back the transaction. I have asynchronous calls to a Restful application that are attempting to update a database object based on some business logic. If I get an OLE, I'd like to retry the transaction after a delay of 0.2-0.5 seconds. @Transactional(rollbackFor = Throwable.class, propagation = Propagation.REQUIRED, readOnly = false) public Response

问题 Suppose I have an entity defined as follows: @Entity public class MyEntity { @Id @GeneratedValue private Integer id; @Column private String name; @Version int version; // Getters + setters } Suppose also I have a service (REST API or something similar) that allows a user to retrieve information about this entity. It returns the ID, the current name, and the current version. There is also another service that allows a user to update the name of an entity. It accepts the ID, update name, and

问题 I'm having trouble implementing optimisitc concurrency in NHibernate in a meaningful way in a web application. Here is the desired scenario: User A opens a form to edit a record User B opens the same form to edit the same record User A saves their data User B tries to save their data but get a warning that the data has been updated. A common scenario. Here is the update code and entity mapping file: <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="Entities" assembly="Domain">

问题 I've been trying to use ISession.Merge() to keep coherence between two sessions, but it fails when the merged instance has a higher Version property than the one loaded in the session (with a StaleObjectStateException). Is there an alternative method that would work when the Version fields do not match ? 回答1: Try calling: Session.Lock(string entityName, object obj, LockMode lockMode); with LockMode.Force. The remarks for that method state: This may be used to perform a version check