db4o Developer Community

My attempt to work with complex Java classes didn't go well. What is a ''complex'' Java class: 3 levels of inheritance, about 80 non-primitive members, among them few 00-sized collections and maps. Well, it all ended on Insertion testing stage - it was slow. Very slow. In the 'success stories' some achieved 200K of simple objects per ...

You may try the SODA equivalent of your desired result. In using native queries, under the hood it is being translated to SODA. Click Here to see a similar thread.

Hi,  My program generates a huge amount of objects. Near 500,000 in abt a minute.Currently it takes like 10 mins to persist all the above no of objects in db4o 6. Is there any kind of tuning I can do to maximize performance?At the moment I am just concerned with writing and not reading.Will going multi-threaded provide any kind of benefit ...

Hi I have a simple question : It would be a good practice to keep the connection open between requests to the database ? For how long by default it can be open ?   Thank 's in advance 

I just found this thread, so I thought I would collect here some questions I had previous posted elsewhere relating to collection needs:Re: equest: lazy activation for collectionshttp://developer.db4o.com/forums/post/45692.aspx- about collections needing to load/activate elements on demand, instead of the entire set:- from the fast collections ...

ObjectContainer.set() is expensive?I was doing some performance tests for a timesheet application I am writing, and was simulating the addition of thousands of item additions through a web service. Ultimately, the logic of the simulation boils down to:  public class Item { int id; String description; Date date; } ... final int ...

Sorry, but I currently do not have the time to strip down an example to show it here. But you may have a look to the attached jprofiler cpu call tree comparison: it shows the difference of cpu usage times for two queries (from within two processes/java vms) ... or do I misinterpret it when saying that there seems to be created some additional ...

Hi there, with querying a db4o db repeatedly several times the same way (ant task: open db, query, close db - no explicite data modification) we observed exponential increase in time needed to fetch the query results. First time it took some milliseconds. In the end after about 20 runs it took minutes. By way of jprofiler (cpu callgraph ...

Hello,   Sorry for the new thread, but the first one I posted became somewhat unclear. In client-server mode, it seems that CPU is going to 100% on the server thread when some client exits without closing its connection. I think, if this is right, that it is a very annoying problem, as this is something that always could happen ...

Hello, Today, I tried the networked client-server db4o flavour. It seems to work great for most things, but one: when my (swing) client is closed, cpu usage is going to 100% (or 50%, dual core) :-( . It isn't the case when the client is running, everything seems to work as planned. If, on the server, I do a ...