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forum_thread

Restrict by class in query

I have the following bit of code: ... I would have assumed that the class parameter would cause results to be restricted to only objects of type Folder (I have a class ...

 
forum_thread

performance limit

Hi, can someone share expirience with performance limits of ObjectDB especialy when quering tables with large records sets. Our issue is with tables with 100.000+ records. Everything was OK when we had few thousand records. We have a simple SELECT statement which selects from a table with 100.000+ records by UserID atribute, tables have from 5 to 20 atributes. Usualy the results range from few hundred to few thousand records. This query takes up to 12 seconds. Is this normal, what when we will have few milion records, how to handle this. ... atribute, tables have from 5 to 20 atributes. Usualy the results range from few hundred to few thousand records. This query takes up to ... Runing this query on 150.000 records gives 126 results in 15 ms for user A. Using this query for username B gives 6500 results ...

 
release

2.6.8

... in handling large objects with long primary keys as query results ( issue #260 ). Fixed detachment of embedded objects to ... Fixed a bug of returning managed hollow objects in query results. Fixed an error message for invalid DELETE query ( issue ...

 
forum_thread

500Mb ObjectDb database opening issue

Hi, I have observed that 500 Mb objectDb database opening time is very slow (~3 seconds) for following code m_EntityMgrFactory = Persistence.createEntityManagerFactory( "objectdb:" + aFilename ); m_EntityManager = m_EntityMgrFactory.createEntityManager(); Does exist any way to speed-up open time for big databases? Definitely, it's too long for 500 Mb database! ... the test application. Strangely, we get different results: 1/23/2016 15:38:42.3842: INFO : ( AppPropertyManager. ... } } } and the results are: Open temp.odb time: 493 Open ... Slow Open.odb.pa3 time: 22 These results show that opening your specific database takes less than 100 ...

 
api-jpa

orderBy(o)

Specify the ordering expressions that are used to order the query results.(Method of javax.persistence.criteria.CriteriaQuery)

 
api-jpa

javax.persistence.criteria.Order

An object that defines an ordering over the query results.(Interface of JPA)

 
api-jpa

javax.persistence.criteria.Fetch

Represents a join-fetched association or attribute.(Interface of JPA)

 
forum_thread

find() delay

Hi, I tried objectdb in following steps: 1, for 1 to 30 {trans.begin(); create typeC o; em.persist(o); trans.commit();} 2, for 1 to 30 {p = em.find(typeC.class, i); print(p)} So simple a test, there is no result in one go; I have to disable step 1 and run again, then Step 2 output the expected results. I tried em.flush(), em.clear(), etc.. that do not work. Any idea? TIA ... step 1 and run again, then Step 2 output the expected results. I tried em.flush(), em.clear(), etc.. that do not work. ...

 
manual

Locking in JPA

Explains how to use optimistic locking and pessimistic locking in JPA. JPA 2 supports both optimistic locking and pessimistic locking . Locking is essential to avoid update collisions resulting from simultaneous updates to the same data by two concurrent users. Locking in ObjectDB (and in JPA) is always at the da ...

 
api-jpa

javax.persistence.criteria.FetchParent

Represents an element of the from clause which may function as the parent of Fetches.(Interface of JPA)