XADM: Exchange Database Engine Doesn't Detect Removed Page in B- tree Split Operation

ID: Q181824

The information in this article applies to:

SYMPTOMS

The Microsoft Exchange information store database may experience one of the following symptoms during normal operation:

During an offline defrag (ESEUTIL /D) of the database, the process stops with JET error -1601(JET_errRecordNotFound) or -1603 (JET_errNoCurrentRecord).

In 5.5 Sp1 during an Offline Defrag (Eseutil /d), the process may stop with J ET error -1526 (JET_errLVCorrupted).

During normal operation, you may get a -1069 error (JET_errVersionStoreOutOfMemory) in the application log. 


  Event ID: 1101
  Source: MSExchangeIS Private
  Type: Error
  Category: Background Cleanup
  Description:
  Error 0xfffffbd3 occurred on message <Message ID> during a background cleanup.
If you run the consistency checker (ESEUTIL /G <db> /V /X piped to a text file), it reports ERROR: corrupted LV(number) (lid changed without root).

In 5.5 Sp1, Eseutil /g /v /x may stop with the following JET Error -1206 (JET_errDatabaseCorrupted).

With Diagnostic Logging turned up to general on the Information Store you may receive the following Application Event Log: During normal operation, you may get a -1069 error (JET_errVersionStoreOutOfMemory) in the application log. 

   Event ID: 195
   Source: ESE97
   Type: Information
   Category: General
   Description:
   MSExchangeIS ((322) ) Internal trace: lv.cxx@395
The information store service (Store.exe) may access violate during normal operation when it encounters corrupt data.

The information store process is utilizing 100 percent of the CPU time all consumed by one thread (there are occasions when up to three threads will be affected). You can view this by following these steps:
  1. Start the Windows NT Performance Monitor.


  2. From the Edit menu, click Add To Chart...


  3. In the Object drop-down list box, select Thread.


  4. In the Instance list box, select all values that contain "store".


  5. Click the Add button.



CAUSE

When the Exchange database engine goes to insert a record into the binary tree (b-tree), it may find a record with the same primary key that is marked for deletion. Because the node is just marked for deletion and has not been physically deleted yet, the Exchange database engine "undeletes" the node and changes its data to that of the new record. Because the Exchange database engine is changing the data associated with the record, the Exchange database engine may be changing the record's size. If the record becomes too big for the page, the Exchange database engine has to perform a b-tree split. During the split, the Exchange database engine must release the latch on the pages in the tree and then re-latch them when the split is completed. In rare circumstances where the information store cleanup thread comes along in the small delta where the pages were unlatched, the information store cleanup thread may remove the page marked for deletion. When the Exchange database engine tries to re-latch the pages, it does not know the record has been removed. As a result, the information store either stops responding (uses 100 percent processor time in one or more threads) or corrupts the data.


RESOLUTION

Apply the fix described below. The Exchange database engine has been fixed to detect whether the page has been removed and to take appropriate action if it has.

If you have already experienced the corruption symptoms of this problem, you can do the following to repair the corruption with NO loss of data and no need to run ISINTEG -fix:

  1. Make sure the new Ese.dll file described below is in place (\winnt\system32).


  2. Stop the information store service.


  3. Run ESEUTIL /P <dbswitch> /X to repair the corruption.


  4. Restart the information store service.


  5. Perform a FULL online backup of the Information Store service to be sure you have the repaired version of the database backed up.


If you have not experienced any of these symptoms but want to be proactive and prevent this corruption from occurring, make sure the Ese.dll file is in place (\winnt\system32) and restart the information store service.


STATUS

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.5. This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 5.5. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K


This fix is currently available at the following location:
ftp://ftp.microsoft.com/bussys/exchange/exchange-public/fixes/Eng/Exchg5.5/PostRTM/ESE-FIX/


MORE INFORMATION

High CPU utilization or a stoppage of the information store will occur if there are exactly two nodes on the page being split. This is because the Exchange database engine will try to split one record on a page, which is not possible.

Data corruption will occur if there are more than two nodes on the page being split. This is because Exchange database engine will replace the node immediately after the one it intended to insert to.

Additional query words: ese!JetGetTableColumnInfo kbfaq exfaq 


Keywords          : kbusage XADM 
Version           : WINDOWS:5.5
Platform          : WINDOWS 
Issue type        : kbbug

Last Reviewed: July 1, 1999