When Microsoft Project Server 2010 creates a large volume of shadow table records, performance problems may occur. Additionally, the shadow table records may cause severe database bloating in the draft and published databases.
To resolve this issue, apply the following hotfix package:
Description of the Project Server 2010 hotfix package (Pjsrvwfe-x-none.msp): October 25, 2011
We recommend that you apply the hotfix package to the Project Server computer during a period of low usage. When the hotfix package is applied, the Project Server computer will create many deletion records for shadow table records. Performance problems may occur until the volume of shadow table records is reduced.
Knowledge Base article 2596498 describes the hotfix package that will prevent new projects from creating large volumes of shadow table records. Additionally, the hotfix package will reduce the rate at which shadow table records are created for existing projects.
The hotfix package fixes all custom fields that are located in the following shadow tables:
For multivalued custom fields, any edit action will reduce the volume of shadow table records that are related to the custom fields. For single value custom fields, the existing volume of shadow table records will be reduced only when custom fields are deleted. You can manually delete custom fields that cannot be deleted through the user interface (UI).
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.