About access



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


High availability and other pratical questions

Hi,   I've just started developing a mobile app which will use a server side, hopefully handling a lot of processing and traffic. I was inteding to use TomEE+ with built-in OpenJPA and Postgres DB, initially on one master server but as it grows more master servers will be set (in different geo locations/data centers) using some data sync mechanism between them.   Now that i've met ObjectDB I want to check the option using it instead of postgres so I have few questions regarding it: ... server will improve performance. You should be able to access embedded ObjectDB from other Tomcat servers (and also replicate that ...


ObectDb 2.3.6 in OSGi environment

Hello, I'm trying to use ObjectDb within OSGi bundles. I have one bundle for db accens which uses ObjectDb and another bundle which includes the POJO models. Everytime I start in plugin evironement i get an PersistenceException, because my POJO not found. If try the same test in normal Java environment everthing works fine. Can you please advice? Thx Peter ... included com.objectDb as required bundle, and the simple access to the db: @ Override public <T> ... org.junit.runners.ParentRunner.access$000(ParentRunner.java:50) at ... org.junit.runners.ParentRunner.access$000(ParentRunner.java:50) at ... org.junit.runners.ParentRunner.access$000(ParentRunner.java:50) at ...


NegativeArraySizeException on commiting a transaction

Hi, we started to get a java.lang.NegativeArraySizeException from ObjectDB upon changing an object in the DB and committing the transaction. I tried to repair the DB file with Database Doctor, but the same error is happening also on the fixed DB file. Btw. during fixing the DB file an Internal error was thrown (details here: http://www.objectdb.com/database/issue/285 ), but the fixing went on and created a new file. ... specific object. Is there a possibility to get access to the database file to check the problematic object? The stack ...


Is there a function of "drop table" or "delete from table"?

Besides the em.remove() one by one, is there a function of "drop table" or "delete from table"? TIA ... Assuming you use JPA - you have to use the JDO ability to access sequences. The code above passes a negative allocation request to the ...


Replication error on slave restart

I'm trying to enable replication on master server that was running with "recovery" enabled previously. I have copied database file to slave... and so on by manual. It worked fine. But if I restart slave server: ... > <dir path = "/" permissions = "access,modify,create,delete" /> </user > </users ... > <dir path = "/" permissions = "access,modify,create,delete" /> </user > </users ...


Replication failed

Dear support members, I am trying to set up a replication url in objectdb.conf and have the the following error in the log files: [ObjectDB 2.3.4] javax.persistence.PersistenceException Failed to connect to server (Connection refused) (error 522) at com.objectdb.jpa.EMF.createEntityManager(EMF.java:176) My objectdb.conf: ... - is there anything special to do with permissions on file access? Many thanks for help or tips! ...


Performance with large databases

When populating a large database (10s of GBs) performance drops suddenly at a certain time whenever I run the populating application.  Is there typically a database size when indexes can no longer be held fully in memory or some such issue?  The method calls that suddenly start to take the most time are those that retrieve data from the store. ... by ID is expected to be faster, because it enables direct access. Retrieval by an indexed field is usually composed of two steps: ...


stress test -> com.objectdb.o.InternalException: null

I am running a stress test with 2 users, each making a request to the JSON API (which uses as storage ObjectDB) each 50 milliseconds. An API call might have between 1-4 db calls, but they are relatively light, and the db has just a few MB at the moment. After a few minutes I got this exception. If I decrease the load, it doesn't happen. If I increase it, I get it very often. Any solution/fix? A sample project is very hard, if not impossible, to create, because it uses all the system. ... JPA interface Provides access to the metamodel of persistent entities in the persistence unit. See ...


Spring 2.5 LocalContainerEntityManagerFactoryBean, no getSharedCacheMode()

I'm trying to setup Spring + JPA + ObjectDb in my test environment and having trouble with the following: <bean id="EnvDMSEntityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="persistenceUnitName" value="envService"/> <property name="persistenceXmlLocation" value="com/awarepoint/persistence.xml"/> </bean> Here is the stack trace I get: ... getSharedCacheMode , and when ObjectDB tries to access that method the exception is thrown. The problem should be ...