Question

Using SQL, SQL server manager 2008, c-sharp.net 4.0 and ms visual studio professional 2010:

I have been working on a main query for my program, and so far it works exactly as intended.
The only Problem is the amount of time it takes to run.

some times it can take up to 3mins for around 2000 records.

I have been asked to get this query much faster, but in all honesty I’m not sure how I can.

Query is below, it uses a linked server and 4 tables. 3 on one server and the other is local.

USE [ShaftData]
GO
/****** Object:  StoredProcedure [dbo].[GetSalesBuyers]    Script Date: 03/29/2012   10:03:27 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[GetSalesBuyers] 
@Acct varchar(255),
@Cdisc varchar(255),
@bcs varchar(255), 
@From date, 
@Too date
AS
SELECT i.Acct,
   i.Name, 
   i.Document, 
   i.Part, 
   i.Qty, 
   i.Unit, 
   dbo.NEWPareto.Pareto, 
   i.pg,
   dbo.MyPgTable.PgName,
   i.[DateTime],
   i.BinSeqNo,
   i.cdisc,
   i.bcs

FROM   
OPENQUERY(SACBAUTO, 'SELECT dbo.iHeads.acct,
                            dbo.iHeads.name,
                            dbo.iLines.Document,
                            dbo.iLines.Part,
                            dbo.iLines.Pg,
                            dbo.iLines.Qty,
                            dbo.iLines.unit,
                            dbo.iHeads.[DateTime], 
                            dbo.iLines.BinSeqNo, 
                            dbo.Customer.cdisc,
                            dbo.Customer.Bcs
                     FROM Autopart.dbo.iheads INNER JOIN  Autopart.dbo.iLines ON 
                     Autopart.dbo.Iheads.document = autopart.dbo.iLines.document
                     INNER JOIN Autopart.dbo.Customer ON Autopart.dbo.iheads.acct 
                     = Autopart.dbo.customer.keycode
                     GROUP By dbo.iHeads.acct,
                            dbo.iHeads.name,
                            dbo.iLines.Document,
                            dbo.iLines.Part,
                            dbo.iLines.Pg,
                            dbo.iLines.Qty,
                            dbo.iLines.unit,
                            dbo.iHeads.[DateTime],
                            dbo.iLines.BinSeqNo,
                            dbo.Customer.cdisc,
                            dbo.Customer.bcs
                      ') i
left JOIN
dbo.NEWPareto
ON 
i.Part collate SQL_Latin1_General_CP1_CI_AS = dbo.NEWPareto.Part 
left JOIN
dbo.MyPgTable 
ON  
 i.pg collate SQL_Latin1_General_CP1_CI_AS = dbo.MyPgTable.[pGroup]

WHERE

 (i.[DateTime] BETWEEN @From AND @Too)

 AND (@Cdisc > 29 OR i.cdisc = @Cdisc)

 AND(@Acct = '0' 
 OR (@Acct = '1659%' AND i.Acct not Like @Acct) 
 OR (@Acct = '1557%' AND i.Acct Like @Acct)
 OR (@Acct = '18731%' AND i.Acct not Like '1873%' AND i.Acct not Like '1432%') 
 OR (@Acct != '1659%' AND i.Acct Like @Acct)) 

 AND(@bcs = '0' OR i.bcs != @bcs)

 AND i.pg != '60'
 AND i.pg != '61'
 AND i.pg != '62'

 GROUP BY i.Acct,
   i.Name, 
   i.Document, 
   i.Part, 
   i.Qty, 
   i.Unit, 
   dbo.NEWPareto.Pareto, 
   i.pg,
   dbo.MyPgTable.PgName, 
   i.[DateTime],
   i.BinSeqNo,
   i.cdisc,
   i.bcs

As you can see its pretty long but works fine, is there any way to drastically increase the speed? or is working with linked servers the problem?

Thanks to all of you for Helping me with this Question, I would love to select you all for the right answer, but I cant, so instead Up votes for all!

Answer 1

Left Joins always make a query a lot slower, doing this across multiple databases will make it even slower.

There is also a Group by in the OpenQuery and again one at the end. Maybe replacing the OpenQuery with a temporary table (with an index on the column i.parts and i.pg) would speed things up.