db4o provides a wide range of configuration options to help you meet your performance and reliability requirements. The following example shows how different configurations affect update performance:
UpdatePerformanceBenchmark.cs: RunConfigurationTest private void RunConfigurationTest() { System.Console.WriteLine( "Update test with different configurations"); // Clean(); Init(); System.Console.WriteLine("Update test: default configurations"); Open(Db4oFactory.NewConfiguration()); Store(); UpdateItems(90); Close(); // Clean(); System.Console.WriteLine("Update test: memory IO adapter"); Open(Configure()); Store(); UpdateItems(90); Close(); // Clean(); System.Console.WriteLine("Update test: cascade on Update"); Open(ConfigureCascade()); Store(); UpdateTopLevelItems(90); Close(); // Clean(); System.Console.WriteLine("Update test: Transparent Persistence"); Open(ConfigureTP()); StoreActivatableItems(); UpdateActivatableItems(90); Close(); }
UpdatePerformanceBenchmark.cs: UpdateItems private void UpdateItems(int count) { StartTimer(); IObjectSet result = objectContainer.QueryByExample(null); for (int i = 0; i < count; i++) { if (result.HasNext()) { Item item = (Item)result.Next(); item._name = "Updated"; Update(item); } else { count = i; break; } } StopTimer("Updated " + count + " items"); }
UpdatePerformanceBenchmark.cs: UpdateTopLevelItems private void UpdateTopLevelItems(int count) { StartTimer(); IQuery query = objectContainer.Query(); query.Constrain(typeof(Item)); query.Descend("_name").Constrain("level0").StartsWith(true); IObjectSet result = query.Execute(); for (int i = 0; i < count; i++) { if (result.HasNext()) { Item item = (Item)result.Next(); item._name = "Updated"; Update(item); } else { count = i; break; } } StopTimer("Updated " + count + " items"); }
UpdatePerformanceBenchmark.cs: UpdateActivatableItems private void UpdateActivatableItems(int count) { StartTimer(); IQuery Query = objectContainer.Query(); Query.Constrain(typeof(ActivatableItem)); Query.Descend("_name").Constrain("level0").StartsWith(true); IObjectSet result = Query.Execute(); for (int i = 0; i < count; i++) { if (result.HasNext()) { ActivatableItem item = (ActivatableItem)result.Next(); item.Name = "Updated"; Update(item); } else { count = i; break; } } StopTimer("Updated " + count + " items"); }
UpdatePerformanceBenchmark.cs: Configure private IConfiguration Configure() { IConfiguration config = Db4oFactory.NewConfiguration(); // using MemoryIoAdapter improves the performance // by replacing the costly disk IO operations with // memory access config.Io(new MemoryIoAdapter()); return config; }
UpdatePerformanceBenchmark.cs: ConfigureCascade private IConfiguration ConfigureCascade() { IConfiguration config = Db4oFactory.NewConfiguration(); // CascadeOnUpdate can be a performance-killer for // deep object hierarchies config.ObjectClass(typeof(Item)).CascadeOnUpdate(true); return config; }
UpdatePerformanceBenchmark.cs: ConfigureTP private IConfiguration ConfigureTP() { IConfiguration config = Db4oFactory.NewConfiguration(); // With Transparent Persistence enabled only modified // objects are written to disk. This allows to achieve // better performance config.ObjectClass(typeof(Item)).CascadeOnUpdate(true); return config; }
UpdatePerformanceBenchmark.cs: ActivatableItem public class ActivatableItem : IActivatable { private string _name; public ActivatableItem _child; [System.NonSerialized] IActivator _activator; public void Bind(IActivator activator) { if (_activator == activator) { return; } if (activator != null && _activator != null) { throw new System.InvalidOperationException(); } _activator = activator; } public void Activate(ActivationPurpose purpose) { if (_activator == null) return; _activator.Activate(purpose); } public ActivatableItem() { } public ActivatableItem(string name, ActivatableItem child) { Name = name; _child = child; } public string Name { get { return _name; } set { _name = value; } } }
The results:
Update test with different configurations
Update test: default configurations
Store 90000 objects: 7869ms
Updated 90 items: 471ms
Update test: memory IO adapter
Store 90000 objects: 6622ms
Updated 90 items: 289ms
Update test: cascade on update
Store 90000 objects: 6848ms
Updated 90 items: 1531ms
Update test: Transparent Persistence
Store 90000 objects: 6604ms
Updated 90 items: 1297ms
From the results you can see that MemoryIoAdapter allows to improve performance, CascadeOnUpdate option results in a considerable drop of performance, and Transparent Persistence makes it better again.
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