Gerod Serafin's WebLog

Helping to keep large organizations' e-mail running


Exchange 5.5 and the "Match Max Open Tables" Registry Key

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OK, if you are an Exchange Administrator you probably are trying to keep your hotfixes up to date, right?  The most recent version of Store.exe is probably 5.5.2658.16 which is mentioned in 841639 Delegate recipient receives two update messages when a meeting request.  I am not recommending that you install this fix however, unless you are experiencing the issue.  Most of you are probably on version 5.5.2658.4 which is part of the 841765 May 2004 Update Rollup for Exchange Server 5.5

So, some of our customers are seeing the following errors in their event logs:

Event ID: 1101
Source: MSExchangeIS Private
Type: Error
Description: Error 0xfffffbd3 occurred on message (some number) during a background cleanup

Event ID: 160
Source: ESE97
Type: Warning
Description:  MSExchangeIS (Store.exe PID) Background clean-up skipped pages. Database may benefit from online or offline defragmentation.

So, we do a quick search of the KBs and look to see if there is anything that mentions these event IDs (1102 and 160) and find the article 293836 Information Store performance degradation caused by excessive scanning.  Looking at the article we see that the Store.exe version of that fix is 5.5.2654.89.  Hmmm... Well since we have a newer version of Store.exe, we shouldn't be seeing this then, should we? 

Looking deeper in the article we see the following paragraph:

To resolve this problem in Exchange Server 5.5, the Preferred Max Open Tables value must be set equal to the Max Open Tables value when the Information Store service starts. To do this, the Match Max Open Tables registry key is added in this fix. If this key is present and set to any value other than zero, the information store automatically sets the Preferred Max Open Tables value equal to the Max Open Tables value.

This can give the reader the idea that the registry key has been added and all is set.  But, if you look for the registry key at HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\ParametersSystem you will not find it there.  The hotfix enables the key to be used to fix the issue, but it doesn't put the key in there.

So, in an effort to be proactive and prevent this issue from occurring in the future, can you push this key out across all of your organization's Exchange servers?  Yes, you can.  There will be no harm in doing that.  In fact, I would recommend it.

If you just want to create a .reg file and add it to your servers, just add the content below to a text file renamed with a .reg extension.

Windows Registry Editor Version 5.00

"Match Max Open Tables"=dword:00000001

  • And if you have that applied and it STILL happens???