Delivery of Mail to Local Users Not Prompt

• Microsoft Commercial Internet System version 2.0
• Microsoft SQL Server version 6.5

SYMPTOMS

When incoming mail is destined for local users the e-mail messages build up in the Queue folder on the mail server and are delivered slowly. There may be a large number of local e-mail messages (.eml files) without corresponding local transaction (extension .ltr) files.

CAUSE

If the database containing the Membership directory is not processing the requests from the LDAP server fast enough, then the messages waiting to be processed will queue up.

RESOLUTION

This problem may be caused by inefficient query optimization if the Membership database is on a SQL Server 6.5 server. SQL Server 6.5 requires that you manually update database statistics as the database table and index sizes change over time. This makes sure that the SQL Query Optimizer selects the optimal indexes for the processing of database requests. Failure to periodically update the database statistics can result in dramatic performance degradation as the database characteristics change.

You can execute the following commands against each Membership Directory database in the system (including all partition databases) regularly to ensure the statistics are up to date:

   DBCC UPDATEUSAGE (0, Object_Lookup) WITH NO_INFOMSGS, COUNT_ROWS 
   go
   
   DBCC UPDATEUSAGE (0, Objects_Attributes) WITH NO_INFOMSGS, COUNT_ROWS
   go
   
   Update statistics Object_Lookup
   go
   
   Update statistics Object_Attributes
   go
   
   Sp_recompile Object_Lookup
   go
   
   Sp_recompile Object_Attributes
   go 

WORKAROUND

Use SQL Server 7.0 for the Membership database. SQL Server 7.0 automatically updates database statistics.

MORE INFORMATION

When MCIS Mail receives a message destined for a local user it queries the LDAP server to obtain further information on the user. LDAP in turn queries SQL Server for the user information. This request takes the form of a stored procedure (sp_ims if the IMS-optimized stored procedures are not enabled, sp_ims1 or sp_ims25 if they are). The longer the stored procedures take to return, the longer local mail will take to be delivered.

To test if these stored procedures are running promptly run the procedures against the membership database manually with a couple of valid local e-mail addresses, for example:

   EXEC sp_ims 'user1@localdomain.com', 
   'user2@localdomain.com' 

REFERENCES

The Microsoft Site Server 3.0 Membership Directory Configuration and Tuning Guidelines document, available in the MCIS 2.5 resource kit at:

http://www.microsoft.com/mcis/reskit/rk_start.htm

Additional query words: mcis mail LDAP local queue

Keywords : kbSQLServ650
Version : winnt:2.0,6.5
Platform : winnt
Issue type : kbprb