db4o Developer Community

Hello. I'm using a database with 1500 complex objects. When I make a query with a ''where'' clause the time it spends is around 0.7-1 second. The strange case happens if I remove the ''where'' clause, I supposed it should be faster than with it but the time increase to 20 seconds. Could you explain this to me, please?   Thanks! 

Hi, Recently we decided to evaluate how much impact (in performance) reflection represented in db4o. In .Net side we already knew (due to previous experience) that reflection is not as fast as we would like to. At the same time, profiling proved that reflection was not a bottleneck in Java side. So we settled up for trying to replace the ...

With LINQ to SQL, the query model is very explicit: if you make a query that can't be performed in SQL, an exception is thrown:    var results = from user in database.Users                     where Fobnicate(user.Name) == Fobnicate(''Jim'') // Exception: no SQL equivalent of Fobnicate                     select user;      But with DB4O, no ...

Hi,Thank you very much for reporting the issue.Current implementation (in SVN) improved this time to something around 6 seconds (running on an emulator; running in an actual device should be faster)Note that the first time a Linq query is executed various assemblies must be loaded from the disk (flash memory); also, device cpus are slower than a ...

After his last blog post about integrating db4o with Grails here's Steve Zara's follow up blog post about testing db4o performance. For this usecase db4o proved to be much faster than an ORM solution and also as fast a pure cache system with all the advantages of using a database system (eg queries). Way to go!

Hello, I am using db4o in a ~1000 (very complex) objects database. Queries run very very slow, so I read the ''Performance Hints'' here: http://developer.db4o.com/Resources/view.aspx/Reference/Tuning/Performance_Hints The configuration that optimizes best the performance is the following: Db4o.configure().callConstructors(true);If I use ...

I am learning db4o and like it a lot. Obviously I testing performance. And I do have a problem with the following.I am using SODA.My database contains 2 000 Products, 30 100 Customers and 300 100 Orders.An Order contains a reference to a Product instance and a Customer Instance.I have one index on Customer.LastName, Order.Amount and ...

Hi! Thanks for sharing this info. Have you tried the NonFlushingIoAdapter? Best.

We invite you to participate in the db4o performance contest which will give away 6000 USD in prizes! Basically participants will provide patches to the db4o core that impact on performance and then these modifications will be judged by the community to select the winners. In order to make the whole process easier we're providing the ...

In this session Carl and Norberto demonstrate how to get started with the 1st db4o performance contest. (Watch on-line without downloading here)