db4o Developer Community

I'm having a problem with poor performance for this query (C#):private Contact GetContactSODA(){    IQuery query = db.Query();    IConstraint firstConstr = query.Descend(''m_name'').Constrain(''mjcb'');    query.Descend(''m_city'').Constrain(''1'').And(firstConstr);    IObjectSet result = ...

I work for a company that is evaluating DB4o, but we have come across some performance issues.  I understand that the .NET version of DB4o includes all the optimization functionality.  I am using .NET 3.0 and DB4o 6.105, and the queries that I am executing aren't being optimized, even when ...

I'm playing around with db4o to see if I can use if for future projects. I have created a simple application with one entity to store. The entity has a string data member that I require to be unique. I will always retrieve objects based on this data member thus I removed the class index and and defined a new one for the data ...

I noticed that Db4o doesnt seem to have an efficient caching mechanism for activated objects, or rather efficient in my opinion :). For example if I activate every object in a fairly deep graph, then perform a query on a top level parent object it still takes a substantial amount of time to retrieve those objects. Even though all the objects ...

I know what you mean.  While we appreciate greatly the speed with which we could get our app going using db4o, we remain, well, perplexed at the aura of performance surrounding db4o's marketting.  Our development has slowed to a crawl now as we try to scale up and end up building our own caches and think about building our own ...

How do you write a fast program? Easy: It should only do what is absolutely necessary with the smallest number of steps possible. Isn't that ultimate laziness? Lazy == Fast ! With this idea in mind we were looking for ways to do less work in our query processor and to empower your application to be able to tell db4o to do less work. The solution ...

Hi, as you may know the Query processor was recently rewritten for our new BTrees. We are now working on further performance improvements, that have become possible with our new BTree algebra code. ObjectSet over BTrees ( #COR-209 ) is one of the tasks we are working on. Instead of creating an intermediate representation of IDs for a ...

Below is some source code that stores 500,000 objects. It alternates between storing 1 object and committing and storing 5000 objects and committing. To me the scalability of store and commit timings does not look like it is increasing exponentially. Time measurements at the beggining of the series: Single 46msObjects: 1Bulk 469msObjects: ...

I have just tried benchmarking db4o and found its performance to be severly lacking, I can't belive that its so slow so its got to be something I'm not doing right. Using a modified version of the pilot example from chapter one I created 100,000 objects. For all the pilot's I set up their points to = 1. I then wanted to run a report which add's ...

The above way to set up your query is perfect. ....if you use the latest 5.7 build which is just about ready. See: http://developer.db4o.com/blogs/product_news/archive/2006/09/18/New-BTree-Field-Index-Processor.aspx   After you have had the chance to try out 5.7, please post back how the results changed. We would love to hear about it.