MSSQL 2016: Unique table computation failed

Microsoft.SQLServer.2016.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.

Overrideable Parameters

Name	Description	Default Value
Enabled	Enables or disables the workflow.	Yes
Priority	Defines Alert Priority.	1
Severity	Defines Alert Severity.	2

Element properties:

Target

Microsoft.SQLServer.2016.DBEngine

Category

EventCollection

Enabled

True

Event_ID

16959

Event Source

$Target/Property[Type="SQL2016Core!Microsoft.SQLServer.2016.DBEngine"]/ServiceName$

Alert Generate

True

Alert Severity

Error

Alert Priority

Normal

Remotable

True

Alert Message

MSSQL 2016: Unique table computation failed

{0}

Event Log

Application

Comment

Mom2016ID='{E8827C4D-1683-4BC1-915A-32FB2D21441B}';MOM2016GroupID={467ECC75-C5DA-42BD-955C-A73BBB51AF74}

Member Modules:

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

Source Code:

<Rule ID="Microsoft.SQLServer.2016.Unique_table_computation_failed_1_5_Rule" Target="SQL2016Core!Microsoft.SQLServer.2016.DBEngine" Enabled="true" ConfirmDelivery="true" Remotable="true" Comment="Mom2016ID='{E8827C4D-1683-4BC1-915A-32FB2D21441B}';MOM2016GroupID={467ECC75-C5DA-42BD-955C-A73BBB51AF74}">

  <Category>EventCollection</Category>

  <DataSources>

    <DataSource ID="_F6DA1507_12AF_11D3_AB21_00A0C98620CE_" Comment="{F6DA1507-12AF-11D3-AB21-00A0C98620CE}" 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>$Target/Property[Type="SQL2016Core!Microsoft.SQLServer.2016.DBEngine"]/ServiceName$</Value>

              </ValueExpression>

            </SimpleExpression>

          </Expression>

          <Expression>

            <SimpleExpression>

              <ValueExpression>

                <XPathQuery>EventDisplayNumber</XPathQuery>

              </ValueExpression>

              <Operator>Equal</Operator>

              <ValueExpression>

                <Value>16959</Value>

              </ValueExpression>

            </SimpleExpression>

          </Expression>

        </And>

      </Expression>

    </DataSource>

  </DataSources>

  <WriteActions>

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

      <Priority>1</Priority>

      <Severity>2</Severity>

      <AlertMessageId>$MPElement[Name="Microsoft.SQLServer.2016.Unique_table_computation_failed_1_5_Rule.AlertMessage"]$</AlertMessageId>

      <AlertParameters>

        <AlertParameter1>Event ID: $Data/EventDisplayNumber$. $Data/EventDescription$</AlertParameter1>

      </AlertParameters>

      <Suppression>

        <SuppressionValue/>

      </Suppression>

    </WriteAction>

  </WriteActions>

</Rule>