About SECOND

api-jpa

javax.persistence.TypedQuery

Interface used to control the execution of typed queries.(Interface of JPA)

 
api-jdo

javax.jdo.Query

The Query interface allows applications to obtain persistent instances, values, and aggregate data from the data store.(Interface of JDO)

 
forum_thread

Performance issues on aggregate query

we are using this aggregate query to collect some data: ... ObjectNode.childNodes the query takes around 1 second. when we query objects that have typically 30-50 objects linked ... ObjectNode.childNodes the query takes around 16 second. For us that seems strange as the relationship ...

 
forum_thread

Connection performace after upgrade to objectdb 2

Hi, I have a problem with objectdb 2 when I tried to get the PersistenceManagerFactory and PersistenceManager : In objectdb 1 : PersistenceManagerFactory pmf = JDOHelper.getPersistenceManagerFactory(getProperties(physicalPath, objectName), JDOHelper.class.getClassLoader()); takes only 3ms PersistenceManager pm = pmf.getPersistenceManager(); takes 40ms However, with objectdb 2, the same instructions take respectively : 257ms and 238ms which is very expensive. #1 2012-12-10 17:32 Hi, I have performance problems with objectdb 2 when I tried to get the PersistenceManagerFactory and Per ...

 
forum_thread

Pessimistic Lock Timeouts setting

Hi,   I realise that JPA2 doesn't necessarily define a standard API way for Lock Timeouts. However, there is a standardised query 'hint' that can be setup to make the underlying DB lock a record for a specific time. The hint property is: "javax.persistence.lock.timeout" #1 2011-04-29 04:30 Hi,   I realise that JPA2 doesn't necessarily define a standard API way for Lock Timeouts. Howev ...

 
manual

FROM clause (JPQL / Criteria API)

Explains how to use the FROM clause and JOIN expressions in a JPA/JPQL query.... has two range variables and a WHERE clause. However, this second query form that uses a join variable is preferred. Besides being shorter and cleaner, the second query describes the right and efficient way for executing the query ...

 
forum_thread

Master database switching to read-only mode, possibly caused by slave failure

We had a database failure causing a production outage. Both master and slave databases have failed, slave became unresponsive and the master switched to read-only mode. By the look of it the slave database failed first and possibly caused the master to switch to read-only mode. The sequence of events was: #1 2012-04-05 04:38 We had a database failure causing a production outage. Both master and slave databases have failed, slave became ...

 
forum_thread

ODB IndexActivation NullPointerException

Hi, We have created indexes on an existing database, which has 4.3 million objects. As soon we create first query, NullPointerException is thrown: #1 2016-04-23 09:55 Hi, We have created indexes on an existing database, which has 4.3 million objects. As soon we create fir ...

 
issue

new objects not available in mappedBy associations

Given a mappedBy association: e.g: @OneToMany(mappedBy="department") public List <Employee> employees;   creating a new mapped class, e.g. new Employee, won't result in this object being available in the same transaction: ie: for (Employee e : department.employee) won't include the new object, even if it is persisted, and even if the transaction is committed??  ... I was expecting that the object would be returned in the second query. Do I need to call refresh() on the object, query, or ... I was expecting that the object would be returned in the second query. That doesn't happen with ordinary queries. Only with ...

 
forum_thread

significant performance decrease

we are using objected in embedded mode (on OS X and WINDOWS). The database increased now to around 400000 entities of one class (database file size around 1.5 GByte). The response time of standard queries increased with this database size to an unacceptable rate (several seconds compared to around 30% when the number of entities was just half of the current). We tried to optimize the cache settings, current objectdb.conf is: <!-- ObjectDB Configuration --> <objectdb> #1 2016-03-15 14:57 we are using objected in embedded mode (on OS X and WINDOWS). The database increased now to around 400000 entitie ...