This view is taking me HOURS to execute:
USE [SalesDWH]
GO
/****** Object: View [dbo].[FirstLastEstablished] Script Date: 10/29/2012 15:12:47 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER view [dbo].[FirstLastEstablished] as
with cte_min as(
select
a.client_id
,a.specimen_source
,a.received_date
from
millennium_dw_dev..F_ACCESSION_DAILY a
join
(select distinct
f.client_id
,f.received_date
,f.accession_daily_key
from
millennium_dw_dev..F_ACCESSION_DAILY f
join
(select CLIENT_ID, MIN(received_date) MinRecDate
from millennium_dw_dev..F_ACCESSION_DAILY
group by CLIENT_ID) i
on f.CLIENT_ID=i.CLIENT_ID
and f.RECEIVED_DATE=i.MinRecDate) b
on
a.ACCESSION_DAILY_KEY=b.ACCESSION_DAILY_KEY
)
,
cte_max as
(
select
a.client_id
,a.specimen_source
,a.received_date
from
millennium_dw_dev..F_ACCESSION_DAILY a
join
(select distinct
f.client_id
,f.received_date
,f.accession_daily_key
from
millennium_dw_dev..F_ACCESSION_DAILY f
join
(select CLIENT_ID, max(received_date) MaxRecDate
from millennium_dw_dev..F_ACCESSION_DAILY
group by CLIENT_ID) i
on f.CLIENT_ID=i.CLIENT_ID
and f.RECEIVED_DATE=i.MaxRecDate) b
on
a.ACCESSION_DAILY_KEY=b.ACCESSION_DAILY_KEY
)
,
cte_est as
(
select distinct client_id, MLIS_DATE_ESTABLISHED
from millennium_dw_dev..D_CLIENT
where REC_ACTIVE_FLG=1
and MLIS_DATE_ESTABLISHED is not null
)
,
mainQuery as(
select distinct
f.client_id
,cmin.specimen_source first_specimen_source
,cmin.received_date first_received
,cmax.specimen_source last_specimen_source
,cmax.received_date last_received
,cest.MLIS_DATE_ESTABLISHED MLIS_DATE_ESTABLISHED
from millennium_dw_dev..F_ACCESSION_DAILY f
left join cte_max cmax
on cmax.CLIENT_ID=f.CLIENT_ID
left join cte_min cmin
on cmin.CLIENT_ID=f.CLIENT_ID
left join cte_est cest
on cest.CLIENT_ID=f.CLIENT_ID
)
,
DateDifferences
as
(
SELECT
client_id,
(DATEDIFF(dd, MLIS_DATE_ESTABLISHED,first_received) + 1)
-(DATEDIFF(wk, MLIS_DATE_ESTABLISHED,first_received) * 2)
-(CASE WHEN DATENAME(dw, first_received) = 'Sunday' THEN 1 ELSE 0 END)
-(CASE WHEN DATENAME(dw, MLIS_DATE_ESTABLISHED) = 'Saturday' THEN 1 ELSE 0 END)
-(case when cast('01/01/2008 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('05/26/2008 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('07/04/2008 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('09/01/2008 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('11/27/2008 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('12/25/2008 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('01/01/2009 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('05/25/2009 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('07/03/2009 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('09/07/2009 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('11/26/2009 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('12/25/2009 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('01/01/2010 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('05/31/2010 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('07/05/2010 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('09/06/2010 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('11/25/2010 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('12/24/2010 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('01/03/2011 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('05/30/2011 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('07/04/2011 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('09/05/2011 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('11/24/2011 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('12/26/2011 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('01/02/2012 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('05/28/2012 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('07/04/2012 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('09/03/2012 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('11/22/2012 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
-(case when cast('12/25/2012 ' as date) between MLIS_DATE_ESTABLISHED and first_received then 1 else 0 end)
DifferenceExcludingWeekends
from
mainQuery
)
,
Territory
as
(
select distinct c.client_id,c.MLIS_TERRITORY,s.REGION_NAME
from millennium_dw_dev..D_CLIENT c
left join millennium_dw_dev..D_SALES_HIERARCHY s
on s.TERRITORY_NAME=c.MLIS_TERRITORY
where c.REC_ACTIVE_FLG=1
and s.REC_ACTIVE_FLG=1
)
select mainQuery.*,d.DifferenceExcludingWeekends,Territory.MLIS_TERRITORY,Territory.REGION_NAME
from mainQuery
left join DateDifferences d
on mainQuery.CLIENT_ID=d.CLIENT_ID
left join Territory
on mainQuery.CLIENT_ID=Territory.CLIENT_ID
GO
I did the sql server database tuning on this, and created all the recommended indexes. After 15min of executing the view again, I stopped it.
Are there obvious things that you could kindly point out to me about my query to optimize it more and improve execution time?
I don’t think you are utilizing the “Common” aspect of a CTE. Try putting table: millennium_dw_dev..F_ACCESSION_DAILY in a CTE first (Only the necessary fields and records if possible). Your code selects from this table 8 times (and is this table local?).
Several of your other CTE’s are referenced once, but I can see how one builds on the other. Yes they can help to break-down a complex query into more managable parts, but it may not help with performance.
Performance may not be an issue here, but getting those hard-coded dates into some sort of Holiday/Day-Off table would help as well. Having a date table may be a better route than all these calculations.
Depending on the size of data, putting this into a stored procedure would allow the use of indexed temp tables.