Question

I’m running sql analyzer on the following query

SELECT bl.Invoice_Number, bl.Date_Invoice, ti.TranNo, bt.Description,
    CONVERT(decimal(15,2), bl.Invoice_Amount) AS Invoice_Amount, co.Company_ID, co.Account_Nbr,
    isnull(bl.Reference,' ') as Reference, bl.Billing_Log_RecID AS BillingKey
    FROM [CONN.domain.NET].cwwebapp.dbo.Billing_Log bl
    LEFT JOIN [App].dob.tarInvoice ti
        ON bl.Invoice_Number = dbo._fnStripLeadZeros(ti.TranNo)
    INNER JOIN [CONN.domain.NET].cwwebapp.dbo.Billing_Type bt
        ON bl.Billing_Type_ID = bt.Billing_Type_ID
    LEFT JOIN [CONN.domain.NET].cwwebapp.dbo.Company co
        ON  bl.Company_RecID = co.Company_RecID
    WHERE bl.Date_Invoice >= '2009-05-05'
        AND ti.TranNo IS NULL
        AND bl.Invoice_Amount <> 0
        AND bl.Billing_Type_ID <> 'D'
        AND bl.Billing_Type_ID <> 'P'
--      AND bl.Billing_Type_ID <> 'M'
Order By bl.Invoice_Number

The query runs on the [App] server and connects to [Conn] sql server to do a join
and the diagram is telling me

remote query cost : 62%
customered index scan [App].[dbo].tarInvoice.[PK__...  Cost : 34% 

This query is taking 2 mins to run. Any ideas on how would I go about figuring out how to make this run more efficiently? I”m guessing it has to do with connecting to another sql server on the same network.

thanks in advance.

Answer 1

you are doing a complete scan of the tarInvoice clustered index (touch every index entry), see if you can remove the function call dbo._fnStripLeadZeros(ti.TranNo) so it will use the index.

possibly add leading zeros onto bl.Invoice_Number and join to unaltered ti.TranNo

EDIT

add computed column without leading zeros and add an index:

ALTER TABLE dbo.tarInvoice ADD TranNoZeroFree AS Convert(int,TranNo) PERSISTED 
GO
CREATE NONCLUSTERED INDEX IX_tarInvoice_TranNoZeroFree ON dbo.tarInvoice (TranNoZeroFree) WITH( STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO