How can I prevent a Lazy Spool from happening in my query? - sql

Question

I been struggling to optimize this query,
SELECT
dbo.OE61BLIN.Order_Key
,dbo.OE61BLIN.Doc_Type
,dbo.OE61BHED.Doc__
,dbo.OE61BHED.Inv_Date
,dbo.OE61BHED.Cust__
,dbo.OE61BLIN.Line_Type
,dbo.OE61BLIN.Item__
,dbo.OE61BLIN.Description
,(CASE
WHEN dbo.OE61BLIN.Doc_Type = 'I' THEN dbo.OE61BLIN.Qty_Shipped * dbo.OE61BLIN.Unit_Factor
WHEN dbo.OE61BLIN.Doc_Type = 'C' AND
dbo.OE61BLIN.return_to_inventory_ = 1 THEN -dbo.OE61BLIN.Qty_Shipped * dbo.OE61BLIN.Unit_Factor
ELSE 0
END) AS QTY
,(CASE
WHEN dbo.OE61BLIN.Doc_Type = 'I' THEN dbo.OE61BLIN.Ext_Price
WHEN dbo.OE61BLIN.Doc_Type = 'C' THEN -dbo.OE61BLIN.Ext_Price
ELSE 0
END) * (CASE
WHEN ISNULL(dbo.OE61BHED.Inv_Disc__, 0) <> 0 THEN 1 - (dbo.OE61BHED.Inv_Disc__ / 100)
ELSE 1
END)
AS amount
,dbo.OE61BHED.Inv_Disc__
,dbo.OE61BLIN.ITEM_GROUP
,dbo.OE61BLIN.Category
,ISNULL(dbo.AR61ACST.intercompany, 0) AS intercompany
FROM dbo.OE61BHED
LEFT OUTER JOIN dbo.AR61ACST
ON dbo.OE61BHED.Cust__ = dbo.AR61ACST.Cust__
RIGHT OUTER JOIN dbo.OE61BLIN
ON dbo.OE61BHED.Order_Key = dbo.OE61BLIN.Order_Key
WHERE (dbo.OE61BLIN.Line_Type = 'R')
AND isnull(intercompany,0) != 1
AND (dbo.OE61BLIN.Doc_Type = 'C'
OR dbo.OE61BLIN.Doc_Type = 'I')
Complete estimated execution plan is here
https://www.brentozar.com/pastetheplan/?id=S1htt0rxN
Actual Exectuion Plan
https://www.brentozar.com/pastetheplan/?id=BymztxLgE
I use SQL Sentry Plan Explorer to optimaze it ,
and it suggested that I should add the following two indexes, which I have
But it doesnt improve much, It only removed RID Look Up from plan.
CREATE NONCLUSTERED INDEX [XI_LineTypeDocType_OE61BLIN_12172018]
ON [dbo].[OE61BLIN] ([Line_Type],[Doc_Type])
INCLUDE ([Order_Key],[Item__],[Description],[Category],[Return_to_Inventory_],[Unit_Factor],[Qty_Shipped],[Ext_Price],[ITEM_GROUP])
CREATE INDEX [XI_CustIntercompany_AR67ACST_12172018] ON [GarbageMark].[dbo].[AR61ACST]
([Cust__] ASC)
INCLUDE ([Intercompany])
I am completely stuck on how to aproach this problem.
I see that Lazy Spool is the most expensive operation but I dont know how to remove
or substitute.

Answer 1

Regrettably you don't prefix intercompany in the where clause with its table name so to some extent I'm guessing that the changes you see below. I am going to suggest that you re-arrange your query to avoid the use of right outer join and then, perhaps more importantly, place the intercompany <> 1 condition directly into the left join which
removes the use of ISNULL() from your where clause.
SELECT
dbo.OE61BLIN.Order_Key
, dbo.OE61BLIN.Doc_Type
, dbo.OE61BHED.Doc__
, dbo.OE61BHED.Inv_Date
, dbo.OE61BHED.Cust__
, dbo.OE61BLIN.Line_Type
, dbo.OE61BLIN.Item__
, dbo.OE61BLIN.Description
, (CASE
WHEN dbo.OE61BLIN.Doc_Type = 'I' THEN dbo.OE61BLIN.Qty_Shipped * dbo.OE61BLIN.Unit_Factor
WHEN dbo.OE61BLIN.Doc_Type = 'C' AND
dbo.OE61BLIN.return_to_inventory_ = 1 THEN -dbo.OE61BLIN.Qty_Shipped * dbo.OE61BLIN.Unit_Factor
ELSE 0
END) AS QTY
, (CASE
WHEN dbo.OE61BLIN.Doc_Type = 'I' THEN dbo.OE61BLIN.Ext_Price
WHEN dbo.OE61BLIN.Doc_Type = 'C' THEN -dbo.OE61BLIN.Ext_Price
ELSE 0
END) * (CASE
WHEN ISNULL( dbo.OE61BHED.Inv_Disc__, 0 ) <> 0 THEN 1 - (dbo.OE61BHED.Inv_Disc__ / 100)
ELSE 1
END)
AS amount
, dbo.OE61BHED.Inv_Disc__
, dbo.OE61BLIN.ITEM_GROUP
, dbo.OE61BLIN.Category
, ISNULL( dbo.AR61ACST.intercompany, 0 ) AS intercompany
FROM dbo.OE61BLIN
INNER JOIN dbo.OE61BHED ON dbo.OE61BLIN.Order_Key = dbo.OE61BHED.Order_Key
LEFT OUTER JOIN dbo.AR61ACST ON dbo.OE61BHED.Cust__ = dbo.AR61ACST.Cust__
AND dbo.AR61ACST.intercompany != 1
WHERE dbo.OE61BLIN.Line_Type = 'R'
AND dbo.OE61BLIN.Doc_Type IN ('C','I')
;
I believe the join between OE61BLIN and OE61BHED can be an inner join, if not try using a left join.