MSSQL on Windows: Unique table computation failed

Microsoft.SQLServer.Windows.EventRule.DBEngine.Unique_table_computation_failed_1_5_Rule (Rule)

Unique tables are used by the database client drivers, like Microsoft Access driver for SQL Server, to build updateable queries. For a given SELECT statement, the unique table identifies the table whose row values appear at most once in the result set. When reselecting a row from a result set, the values from the key columns of the unique table are enough to identify the row. This error is raised when the server is unable to compute the unique table.

Knowledge Base article:

Summary

Causes

This error may be raised when the SELECT query has a UNION, GROUP BY, ROLL UP or other aggregates. Unique tables are not defined for these cases.

Resolutions

Re-write the query avoiding the constructs which prevent unique table computation. In most of the error scenarios, updateable result set is not implementable.

Overridable Parameters

Name	Description	Default Value
Enabled	Enables or disables the workflow.	Yes
Interval (seconds)	The recurring interval of time in seconds in which to run the workflow.	300
Priority	Defines Alert Priority.	1
Severity	Defines Alert Severity.	2
Synchronization Time	The synchronization time specified by using a 24-hour format. May be omitted.
Timeout (seconds)	Specifies the time the workflow is allowed to run before being closed and marked as failed.	200
Timeout for query execution (seconds)	The workflow will fail and register an event, if the query execution takes longer than the specified period.	60
Timeout for database connection (seconds)	The workflow will fail and register an event, if it cannot access the database during the specified period.	15

Element properties:

Target

Microsoft.SQLServer.Windows.DBEngine

Category

EventCollection

Enabled

True

Alert Generate

True

Alert Severity

Error

Alert Priority

Normal

Remotable

True

Alert Message

MSSQL on Windows: Unique table computation failed

{2}

Comment

Mom2017ID='{E8827C4D-1683-4BC1-915A-32FB2D21441B}';MOM2017GroupID={467ECC75-C5DA-42BD-955C-A73BBB51AF74}

Member Modules:

ID	Module Type	TypeId	RunAs
_F6DA1507_12AF_11D3_AB21_00A0C98620CE_	DataSource	Microsoft.SQLServer.Windows.DataSource.EventCollectionFiltered	Default
GenerateAlert	WriteAction	System.Health.GenerateAlert	Default

Source Code:

<Rule ID="Microsoft.SQLServer.Windows.EventRule.DBEngine.Unique_table_computation_failed_1_5_Rule" Target="SqlDiscW!Microsoft.SQLServer.Windows.DBEngine" Enabled="true" ConfirmDelivery="true" Remotable="true" Comment="Mom2017ID='{E8827C4D-1683-4BC1-915A-32FB2D21441B}';MOM2017GroupID={467ECC75-C5DA-42BD-955C-A73BBB51AF74}">

  <Category>EventCollection</Category>

  <DataSources>

    <DataSource ID="_F6DA1507_12AF_11D3_AB21_00A0C98620CE_" Comment="{F6DA1507-12AF-11D3-AB21-00A0C98620CE}" TypeID="Microsoft.SQLServer.Windows.DataSource.EventCollectionFiltered">

      <MachineName>$Target/Property[Type="SqlCoreLib!Microsoft.SQLServer.Core.DBEngine"]/MachineName$</MachineName>

      <NetbiosComputerName>$Target/Property[Type="SqlCoreLib!Microsoft.SQLServer.Core.DBEngine"]/NetbiosComputerName$</NetbiosComputerName>

      <InstanceName>$Target/Property[Type="SqlCoreLib!Microsoft.SQLServer.Core.DBEngine"]/InstanceName$</InstanceName>

      <ConnectionString>$Target/Property[Type="SqlCoreLib!Microsoft.SQLServer.Core.DBEngine"]/ConnectionString$</ConnectionString>

      <InstanceVersion>$Target/Property[Type="SqlCoreLib!Microsoft.SQLServer.Core.DBEngine"]/Version$</InstanceVersion>

      <InstanceEdition>$Target/Property[Type="SqlCoreLib!Microsoft.SQLServer.Core.DBEngine"]/Edition$</InstanceEdition>

      <MonitoringType>$Target/Property[Type="SqlDiscW!Microsoft.SQLServer.Windows.DBEngine"]/MonitoringType$</MonitoringType>

      <SqlExecTimeoutSeconds>60</SqlExecTimeoutSeconds>

      <SqlTimeoutSeconds>15</SqlTimeoutSeconds>

      <TimeoutSeconds>200</TimeoutSeconds>

      <IntervalSeconds>300</IntervalSeconds>

      <SyncTime/>

      <EventDisplayNumber>16959</EventDisplayNumber>

    </DataSource>

  </DataSources>

  <WriteActions>

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

      <Priority>1</Priority>

      <Severity>2</Severity>

      <AlertMessageId>$MPElement[Name="Microsoft.SQLServer.Windows.EventRule.DBEngine.Unique_table_computation_failed_1_5_Rule.AlertMessage"]$</AlertMessageId>

      <AlertParameters>

        <AlertParameter1>$Target/Property[Type="SqlCoreLib!Microsoft.SQLServer.Core.DBEngine"]/MachineName$</AlertParameter1>

        <AlertParameter2>$Target/Property[Type="SqlCoreLib!Microsoft.SQLServer.Core.DBEngine"]/InstanceName$</AlertParameter2>

        <AlertParameter3>Event ID: $Data/Property[@Name='EventID']$. $Data/Property[@Name='Message']$</AlertParameter3>

      </AlertParameters>

      <Suppression>

        <SuppressionValue/>

      </Suppression>

    </WriteAction>

  </WriteActions>

</Rule>