XADM: Slow Performance When Opening Unread Item from Public Folder with Many Restrictions

All users attempting to open any unread message item in a particular public folder experience a long delay before the message is opened.

The public folder has many server-side restriction tables (views) associated with it. Whenever a change is made to a message in a folder, or a new message created or deleted, the message must be evaluated against all the server-side restrictions so that they can be updated. Opening an unread message changes the state of the MSGFLAG_READ bit of the PR_MESSAGE_FLAGS MAPI property. Normally, each restriction is represented by a table in the database, and this table must be opened to be updated/evaluated. It is possible, however, for the information store to avoid opening the table if the client operation is simply changing the read/unread state of a message, because the server can tell (without opening the table) if the restriction involves the MSGFLAG_READ bit.

Code was added to the information store to check if the restriction involves the read/unread message flags and if not, it can avoid opening the restriction table (which improves performance).

To resolve this problem, obtain the latest service pack for Exchange Server version 5.5. For additional information, click the following article number to view the article in the Microsoft Knowledge Base: The English version of this fix should have the following file attributes or later:

Component: Information Store

Microsoft has confirmed that this is a problem in Microsoft Exchange Server version 5.5. This problem was first corrected in Exchange Server 5.5 Service Pack 3.