About performance

forum_thread

Embedded server feature

Is it safe to use this wonderful and undocumented feature in production, and rely on its problem-free functioning? For my case it would be really beneficial: 1 physical server with SSD 1 JVM running on it 2 web applications on Tomcat 1 ObjectDB Server deployed, in embedded server mode 2 ObjectDB databases for those 2 webapps, both would use the server in embedded mode for stellar performance ... both would use the server in embedded mode for stellar performance distant access to databases is anyway mandatory, to be able ...

 
issue

Database File Compression

ObjectDB database files are usually smaller than database files of other Database Management Systems (object and Relational) but still, an additional internal compression is possible. Usually smaller files are also faster because less I/O operations are required and memory cache can be used more efficiently. But compression and decompression consumes CPU time. Therefore, the effect of compression on Object databases is currently unknown.... the effect of using compressed ObjectDB database file on performance is unknown yet. ObjectDB Support ...

 
page

What is new in ObjectDB 2.0?

... not enhanced. Improved optimistic locking support. Performance improvement in writing and reading of objects. Level 2 ...

 
forum_thread

Multithreading Test and Deadlock

I move on to testing the multi threaded part of ObjectDB. From the same code (MyMain.java), I set the thread count from 1 to 4 and not only do I found it's slower overall (each thread only needs to insert 250K entities) but the threads are stuck with a deadlock. All threads share the same EntityManagerFactory but they have their own EntityManager. The stack trace is attached. ... in ObjectDB embedded mode multithreading improves performance in reading but not in writing. You can see this in the JPAB ...

 
forum_thread

Exceeding max connections and crashing

Hi, we have severe problems with ObjectDB crashing frequently. We can’t find the exact cause but we suspect several things. We use 2.5.3_03 version and we use it in production. The same setup in test environment hasn’t have these kind of problems First crash occurred when network went down and database lost connection with the JBOSS AS, several restarts got it up and running finally.  It seems when the database loses network connection it shutdowns but we cant be sure. Usualy database stops once a day with no apperent reason. ... enough and we increased it to 5000 but after that system performance degraded significantly. It started to crash less frequently Q1. ...

 
forum_thread

Deadlock problems solved - a suggestion

Thanks to the new logging capability, I have managed to solve all the deadlock problems, as they were a result of Objectdb encountering new classes in multi-threaded code.  I have a suggestion that might be useful for other users - how about an Ant task that, given a database URL, performs the necessary schema changes (including creating the database if necessary), so that a database is already set up with the complete schema before an application runs? #1 2013-05-27 22:55 Thanks to the new logging capability, I have managed to solve all the deadlock problems, as they were a result of ...

 
forum_thread

Cascade delete with unidirectional mapping

    Suppose entity A is referenced from entity B, like (A -> * B) but not actually having that reference, instead only B has @ManyToOne relationship to A and A has none. Is there a way to cascade delete of B's when deleting A? Or this should be done programatically with separate call to database? #1 2014-05-16 14:22     Suppose entity A is referenced from entity B, like (A -> * B) but not actually having that refer ...

 
api-jdo

checkAuthorizedStateManager(sm)

Check that the parameter instance is of a class that is authorized for JDOPermission("setStateManager").(Static Method of javax.jdo.spi.JDOImplHelper)

 
forum_thread

Is it possible get the All PrimKeys for a given entity class in the DB?

Hi, I would like to retrieve all the primKeys (user defined) by doing something like: TypedQuery<MyClassPrimKey> query = em.createQuery("SELECT mif.primkey FROM MyClass mif", MyClassPrimKey.class); The only alternative I can think of - would be to store the primkey on the object - but sounds like it is double storage Thanks ... each time the entity object is loaded. But the effect on performance is expected to be minimal, and the database size will not ...

 
forum_thread

remove() and persist() in same transaction => Attempt to reuse an existing primary key value

Hello Support, in our configuration (FlushModeType.AUTO) is the execution of  em.find(Entity.class, <id>) much faster than an equivalent query. To optimize the Performance we define a special Entity (A) with additional data that use an existing ID of another Entity (B) from another class (another table). On this point we get no conflicts. If we remove additional data for Entity (B) and then the special Entity (A) is empty, we remove the special Entity (A). ... faster than an equivalent query. To optimize the Performance we define a special Entity (A) with additional data that use an ...