No Class Index

.NET: 

configuration.ObjectClass("namespace.classname, assembly").Indexed(false);

Turns class index off.

Advantage

Allows to improve the performance to delete and create objects of a class.

Effect

db4o maintains an index for each class to be able to deliver all instances of a class in a query. In some cases class index is not necessary:

Indexed(false) setting will save resources on maintaining the class index on create and delete of the class objects.

Alternate Strategies

Object creation performance can be improved using configuration.callConstructors(true) setting.

General read/write performance can be improved with the configuration.reserveStorageSpace(byteCount) setting.