About performance

forum_thread

How to use JOIN FETCH?

The ObjectDB manual (http://www.objectdb.com/java/jpa/query/jpql/from) gives an example of using JOIN FETCH to avoid excessive round trips to the database: ... problem, which isn't going to be acceptable from a performance point of view. edit ...

 
issue

Another NPE on em.createQuery(query).getResultList()

Related to #51 that was tested against 2.2.7 and marked as fixed in 2.2.8. Running the same test case against 2.2.8 now results in: ... classes (you should use enhanced classes anyway to improve performance). ObjectDB Support ObjectDB - Fast ...

 
forum_thread

Spring MVC Errors

I try to import the project from the tutorial but when doing so I get errors: 1. http://i.imgur.com/tbIsj.png and then when I try to start it anyways I get things like thaat: 2. http://i.imgur.com/G7UVu.png any ideas ? I installed m2eclipse plugin and Maven Integration for WTP and then I import Maven project from disk and this is what I get ... ;( ... troubles and use alternative methods (or no enhancement if performance is not an issue). The reason for this is unclear. It ...

 
manual

JPA Primary Key

Explains how to define and use primary keys in JPA, including composite and embedded primary keys.... following primary key can significantly improve query run performance: @Entity javax.persistence.Entity JPA ...

 
forum_thread

Embedded & Activation & Scalation

Hi there, Our app is highly scalable and can be distributed among multiple processes on multiple machines. ObjectDB Server is not really scalable right now and would be a SPOF for our application. So, we'd like to embedded odb into each instance instead for now and point each to the same database folder, however I've got a few questions I couldn't find answers for: #1 2012-01-30 07:39 Hi there, Our app is highly scalable and can be distributed among multiple processes on multiple machines ...

 
forum_thread

objectdb-2.6.9_02 (with "objectdb.temp.no-enhancement-crc-check") vs. generic classes with interfaces: detailed investigation

objectdb-2.6.9_02 (with "objectdb.temp.no-enhancement-crc-check" system property) The following is a detailed report on investigation of multiple issues that have been mentioned in the following forum postings and issue reports (but please do not visit them from here now, the diagnostics there are now obsolete): - Issue #282 - ObjectDB-2.6.9: Failed to commit transaction: Failed to set numeric value of field property Element.id using reflection #1 2016-08-21 09:00 objectdb-2.6.9_02  (with "objectdb.temp.no-enhancement-crc-check" system property) The follow ...

 
manual

[ODB1] Chapter 7 - JDOQL Queries

Explains how to use JDOQL, the Java/JDO Query Language. There are various ways to retrieve objects from an ObjectDB database, as shown in section 6.3 . An Extent , for instance, can be used to retrieve all the instances of a specified persistent class. When a more selective retrieval is needed, JDOQ ...

 
forum_thread

EntityManager.refresh takes a long time

EntityManager.refresh takes a long time for entity object Person in this code: ... graph of objects. Here are some tips for improving performance: Avoid  CascadeType.ALL and  ...

 
forum_thread

UserException: Package com.example.model is not found by the enhancer

My program works fine when I run it from Netbeans but as soon as I clean and build and move the dist directory out of the project to a remote location and run it using java -jar example.jar then I get the exception: com.objectdb.o.UserException: Package com.example.model is not found by the enhancer It occurs on this line: com.objectdb.Enhancer.enhance("com.example.model" + ".*"); #1 2014-06-15 12:19 My program works fine when I run it from Netbeans but as soon as I clean and build and move the dist directory ou ...

 
issue

Sometimes the ObjectDB throws an internal expeption if a persist() was executed

[ObjectDB 2.6.6_08] Unexpected exception (Error 990) Generated by Java HotSpot(TM) 64-Bit Server VM 1.8.0_51 (on Windows 7 6.1). Please report this error on http://www.objectdb.com/database/issue/new com.objectdb.o.InternalException: java.lang.NullPointerException: null java.lang.NullPointerException at com.objectdb.o.OBM.bE(OBM.java:395) at com.objectdb.o.OBM.bE(OBM.java:269) at com.objectdb.jpa.EMImpl.persist(EMImpl.java:442) ... the transaction. This step is just to increase the performance, because the first 'persist' of an entity class can take a ...