Home
  •  

Chain sequence numbers are out of order in IAM chain.

Microsoft.SQLServer.2000.Chain_sequence_numbers_are_out_of_order_in_IAM_chain (Rule)

Knowledge Base article:

Causes

Every IAM page has a sequence number, which is its position within the IAM chain. The sequence numbers increase by 1 with every IAM page. This error means that IAM page P_ID2 has a sequence number that does not follow these rules.

Resolutions

HARDWARE FAILURE

Run hardware diagnostics and correct any problems. Also examine the Microsoft® Windows NT® system and application logs and the SQL Server™ error log to see if the error occurred as the result of hardware failure. Fix any hardware related problems.

If you have persistent data corruption problems, try to swap out different hardware components to isolate the problem. Check to ensure that your system does not have write caching enabled on the disk controller. If you suspect this to be the problem, contact your hardware vendor.

Finally, you might find it beneficial to switch to a completely new hardware system, including reformatting the disk drives and reinstalling the operating system.

RESTORE FROM BACKUP

If the problem is not hardware related and a known clean backup is available, restore the database from the backup.

DBCC CHECKDB

If no clean backup is available, execute DBCC CHECKDB without a repair clause to determine the extent of the corruption. DBCC CHECKDB will recommend a repair clause to use. Then, execute DBCC CHECKDB with the appropriate repair clause to repair the corruption.

CAUTION: If you are unsure what effect DBCC CHECKDB with a repair clause has on your data, contact your primary support provider before executing this statement.

CAUTION: Repair will rebuild the IAM chain. It does this with the following steps:

Split the existing chain in two.

The first half of the chain will end with IAM page P_ID1 and its next page pointer will be set to (0:0).

The second half of the chain will begin with IAM page P_ID2 and its prev page pointer will be set to (0:0).

Connect the two chains together and regenerate the sequence numbers for the whole IAM chain. Any irreparable IAM pages will be de-allocated.

CAUTION: This repair may cause data loss.

CAUTION: If running DBCC CHECKDB with one of the repair clauses does not correct the problem, contact your primary support provider.

Element properties:

TargetMicrosoft.SQLServer.2000.DBEngine
CategoryEventCollection
EnabledTrue
Event Source$Target/Property[Type="SQL!Microsoft.SQLServer.DBEngine"]/ServiceName$
Alert GenerateTrue
Alert SeverityError
Alert PriorityNormal
RemotableTrue
Alert Message
Chain sequence numbers are out of order in IAM chain.
{0}
Event LogApplication
CommentMom2005ID='{203AAA36-1B82-44D6-9DE2-30182EDEEDC0}'

Member Modules:

ID Module Type TypeId RunAs 
EventDS DataSource Microsoft.Windows.EventProvider Default
GenerateAlert WriteAction System.Health.GenerateAlert Default

Source Code:

<Rule ID="Microsoft.SQLServer.2000.Chain_sequence_numbers_are_out_of_order_in_IAM_chain" Target="SQL2000Core!Microsoft.SQLServer.2000.DBEngine" Enabled="true" Comment="Mom2005ID='{203AAA36-1B82-44D6-9DE2-30182EDEEDC0}'" Remotable="true">

  <Category>EventCollection</Category>

  <DataSources>

    <DataSource ID="EventDS" TypeID="Windows!Microsoft.Windows.EventProvider">

      <ComputerName>$Target/Host/Property[Type="Windows!Microsoft.Windows.Computer"]/NetworkName$</ComputerName>

      <LogName>Application</LogName>

      <Expression>

        <And>

          <Expression>

            <SimpleExpression>

              <ValueExpression>

                <XPathQuery>PublisherName</XPathQuery>

              </ValueExpression>

              <Operator>Equal</Operator>

              <ValueExpression>

                <Value>$Target/Property[Type="SQL!Microsoft.SQLServer.DBEngine"]/ServiceName$</Value>

              </ValueExpression>

            </SimpleExpression>

          </Expression>

          <Expression>

            <RegExExpression>

              <ValueExpression>

                <XPathQuery>EventDisplayNumber</XPathQuery>

              </ValueExpression>

              <Operator>MatchesMOM2005RegularExpression</Operator>

              <Pattern>^(17052|17055)$</Pattern>

            </RegExExpression>

          </Expression>

          <Expression>

            <RegExExpression>

              <ValueExpression>

                <XPathQuery>EventDescription</XPathQuery>

              </ValueExpression>

              <Operator>MatchesMOM2005BooleanRegularExpression</Operator>

              <Pattern>((^.*2577 and (not ^.*\n.*2577)) or (^.*2577.*\n.*2577)) AND (NOT ^.*[0-9]+.*2577) AND (NOT ^.*2577[0-9]+)</Pattern>

            </RegExExpression>

          </Expression>

        </And>

      </Expression>

    </DataSource>

  </DataSources>

  <WriteActions>

    <WriteAction ID="GenerateAlert" TypeID="SystemHealth!System.Health.GenerateAlert">

      <Priority>1</Priority>

      <Severity>2</Severity>

      <AlertOwner>$Data/PublisherName$</AlertOwner>

      <AlertMessageId>$MPElement[Name="Microsoft.SQLServer.2000.Chain_sequence_numbers_are_out_of_order_in_IAM_chain.AlertMessage"]$</AlertMessageId>

      <AlertParameters>

        <AlertParameter1>$Data/EventDescription$</AlertParameter1>

      </AlertParameters>

      <Suppression>

        <SuppressionValue/>

      </Suppression>

    </WriteAction>

  </WriteActions>

</Rule>