About page


ODB 2 JDO enhancement

If I label a class @PersistenceCapable do I still need to explicitly enhance? Do I need a package.jdo file? This question relates to experiences with ODB 1, in which one has to: a) create a package.jdo, and b) run the Enhancer In my experience, using this with Tomcat, and running the enhancer in the contextListener class, there would often be errors relating to 'class not persistent capable'. So, in ODB 2 is there a way to mark a class as @PersistentCapable, and then let ODB take care of enhancement automatically?... all the three enhancement methods (as explained on that page) also with a web application.   ObjectDB ...



... in queries. Fixed a critical bug in page caching (issues #116 , #119 , #121 ). Fixed a bug ... user count" bug ( issue #83 ). Fixed a page cache purge deadlock ( issue #85 ). Fixed handling ;drop ...


Performance tuning, best practices

we have a system where we serve from a host process around 200 clients connected via webSockets (Jetty). The core process is running on a dedicated Windows 2012 server with 16 GByte RAM and 8 processor cores.  What is strange for us is that max 20% of the cpu resources are used and the IO subsystem is at maximum 30% of activity under heavy load but database queries are let's say not at the speed we would expect. We have currently 20.000.000 objects in the database, our configuration settings are: ...   <size initial="256kb" resize="256kb" page="2kb" />   <recovery enabled="true" sync="false" path="." ...



This class is for identity with a single long field.(Class of JDO)


com.objectdb.o.InternalException: null

After an error in a @PrePersist method in an Entity class, the database stopped working. Fortunately this was in development, but still worrying! The Entity class ... 50 % 60 % 70 % 80 % 90 % 100 %   Page Content Errors ------------------- [ 1 ] Page #10 entry 5 has unexpected field count (1 instead of 12) ...


Indexes broken after schema update

I don't want to keep creating these issues but the Exception tells me to :), I started a thread to see if anyone else has encountered this at http://www.objectdb.com/database/forum/484 ... 19:42:25 #77 store] BTree Page: 7 [2012-08-19 19:42:25 #78 store] Request code: 4 [2012-08-19 19:42:25 ...


trim(ts, x)

Create expression to trim blanks from a string.(Method of javax.persistence.criteria.CriteriaBuilder)



Whether the identifiable type has a single id attribute.(Method of javax.persistence.metamodel.IdentifiableType)


lessThanOrEqualTo(x, y)

Create a predicate for testing whether the first argument is less than or equal to the second.(Method of javax.persistence.criteria.CriteriaBuilder)


setParameter(position, value)

Bind an argument to a positional parameter.(Method of javax.persistence.TypedQuery)