About performance

issue

Explorer bug ? Objects seem to be missing from database in Class view, but are present as references

objectdb-2.2.5_08 NetbeansID6.9.1+Glassfish3.01 I suspect the following is an Explorer bug. It is marked knowingly as CRITICAL by me because it makes the ObjectDB system unusable for a real project because it appears to be either database integrity corruption, or it just looks like it, which is just as bad. I attach a running project illustrating the problem, as well as screenshots. ... times until commit). You should avoid this to improve performance, but of course - ObjectDB must be able to handle such activity ... to SEQUENCE or TABLE  would provide better performance than flush after every persist . ...

 
issue

Pessimistic lock timeout - blocks indefinitely

I've attached a simple test which creates an object then kicks off several threads which each try to update the object. I'm using a pessimistic lock with timeout as follows: Bug Version: 2.3.1 Priority: Normal Status: Fixed Replies: 3 Type:  Bug ...

 
manual

GROUP BY and HAVING clauses

Explains how to use the GROUP BY and HAVING clauses in a JPA/JPQL query. The GROUP BY clause enables grouping of query results. A JPQL query with a GROUP BY clause returns properties of generated groups instead of individual objects and fields. The position of a GROUP BY clause in the query execution order is afte ...

 
forum_thread

Efficient query on EmbeddedId

Hi! I have an entity class with an @EmbeddedId (field1 int and field2 int). Based on the manual, I understand that making a query just on entity.id.field1 is efficient. Of course, making a query containing the whole EmbeddedId is the ideal case, and I use it, but I need more use cases. ... Another question about indexes: is there any insert/query performance difference between defining an index on a primitive field or on an ...

 
forum_thread

Issue with compile time enhancement

I have an entity library which I have integrated build time enhancement in.  The enhancer reports it has processed all of my persistent classes.  When I attempt to run a Bootstrap process with this library I get the error shown below.  The entity referenced in the error (Terms) is listed as having been enhanced. I am running with ObjectDB in embedded mode via a reference to a persistence unit also shown below. Please let me know if you need any additional information to diagnose this problem. Thanks, Joel ... is not required by ObjectDB (although it can improve performance and it is highly recommended), but if you use enhancement all the ...

 
manual

Database Server

Explains how to run and use the ObjectDB object database Server to manage Java/JPA/JDO databases in client-server mode.... you can increase the maximum JVM heap size and improve performance by using HotSpot JVM server mode: > java ...

 
forum_thread

How to resolve 404 errors with Eclipse/Maven Spring MVC

I have created a project as guided by www.objectdb.com/tutorial/jpa/eclipse/spring/run. When I abandon eclipse and use the maven command line to deploy this Spring MVC web app to jetty and point my browser to localhost:8080/Guestbook/ it works as your tutorial says! ... or other method) is optional, but improves performance. You may post your tutorial based Eclipse project that ...

 
forum_thread

High memory consumption even after close() of EntityManagerFactory

Hello, we still have memory usage problems. When debugging, we have now observed a case in which the execution of multiple queries increasingly byte array were generated (about 1.5 GB) which from GC could not be released. Not even after the EntityManagerFactory closed. We created a small test with which you can observe similar behavior. The huge memory usage only occurs if we execute the query (line 56 to 61). If we remove this query, all is well. The memory is only released after we re-run a query (on a different database). #1 2015-09-18 09:55 Hello, we still have memory usage problems. When debugging, we have now observed a case in which the execution of ...

 
forum_thread

Safe Settings

Hi, I am trying to set up ObjectDb in a safe way that allows turning the machine off while database transactions are running. I would like to test if things are really safe and if I don't get corrupted database files in any possible case. I found "recovery" and "recording" in the objectdb.conf file. Which one is safer to use? I suppose I should turn on sync="true", right? ... of durability even when sync is disabled (and the performance would be better). There are many reasons why 100% durability ...

 
forum_thread

calling persist on an object more than once

results in an error (613) when the transaction is commited: [ObjectDB 2.2.4] javax.persistence.RollbackException Failed to commit transaction: Attempt to reuse an existing primary key value (common.model.UserSession:13) (error 613) at com.objectdb.jpa.EMImpl.commit(EMImpl.java:271) at javax.jdo.Transaction$commit.call(Unknown Source)   I submit that there are a number of problems with this: a) the error message is not helpful #1 2011-05-13 03:09 results in an error (613) when the transaction is commited: [ObjectDB 2.2.4] javax.persistence.RollbackEx ...