How to speedup this query? - sql

Question

Do you have some idea of how to speedup this query:
SELECT Vosol = ( CASE WHEN EXISTS ( SELECT Id
FROM trs.CollectionHeaderView AS chv
WHERE chv.ItemNum = itm.ItemNum
AND chv.CollectionType = '1' )
THEN ISNULL(itm.Amount, 0)
ELSE 0
END ) ,
Vakhast = ( CASE WHEN EXISTS ( SELECT Id
FROM trs.CollectionHeaderView AS chv
WHERE chv.ItemNum = itm.ItemNum
AND chv.CollectionType = '2' )
THEN ISNULL(itm.Amount, 0)
ELSE 0
END )
FROM trs.TrsDocRcvItem AS itm
LEFT JOIN trs.TrsDocRcvHeader AS hdr ON itm.HeaderRef = hdr.Id
LEFT JOIN acc.DL AS dl ON dl.Id = hdr.DLRef
LEFT JOIN trs.TrsDocType AS docType ON docType.Id = hdr.DocTypeRef
INNER JOIN sle.SleCustomer AS customer ON customer.DLRef = dl.Id
LEFT JOIN trs.AccOperation AS operation ON operation.Id = itm.AccOperationRef
WHERE hdr.DocTypeRef NOT IN ( 1141, 1142, 1241, 1242 )
AND ( hdr.State = '1'
OR hdr.State = '2'
)
AND operation.StateType = '1'
I'm trying to optimize sql query which now takes about 6 second to execute.
What more can I do to speedup this query?
I'm using Microsoft Sql Server.

Answer 1

Use OUTER APPLY to remove the two correlated sub-queries.
SELECT Vosol = CASE WHEN chv1 IS NOT NULL THEN Isnull(itm.Amount, 0) ELSE 0 END,
Vakhast = CASE WHEN chv2 IS NOT NULL THEN Isnull(itm.Amount, 0) ELSE 0 END
FROM trs.TrsDocRcvItem AS itm
INNER JOIN trs.TrsDocRcvHeader AS hdr
ON itm.HeaderRef = hdr.Id
--LEFT JOIN acc.DL AS dl
-- ON dl.Id = hdr.DLRef
--LEFT JOIN trs.TrsDocType AS docType
-- ON docType.Id = hdr.DocTypeRef
--INNER JOIN sle.SleCustomer AS customer
-- ON customer.DLRef = dl.Id
INNER JOIN trs.AccOperation AS operation
ON operation.Id = itm.AccOperationRef
OUTER apply (SELECT Max(CASE WHEN chv.CollectionType = '1' THEN id END) AS chv1,
Max(CASE WHEN chv.CollectionType = '2' THEN id END) AS chv2
FROM trs.CollectionHeaderView AS chv
WHERE chv.ItemNum = itm.ItemNum
AND chv.CollectionType IN ( '1', '2' )) oa
WHERE hdr.DocTypeRef NOT IN ( 1141, 1142, 1241, 1242 )
AND hdr.State IN ( '1', '2' )
AND operation.StateType = '1'
I have commented out the acc.DL and sle.SleCustomer tables. I don't see any use of it other than filtering records. If you really need it then uncomment it.
Also I have commented the trs.TrsDocType table which again has no use. Unless it has one to many relationship with trs.TrsDocRcvHeader table. If it has one to many relationship then the result simply get duplicated for no reason since you are not selecting anything from trs.TrsDocType table.
Still if the query is running slow then you need to create Indexes on the tables involved. Also make sure the statistics are up-to-date
After analyzing your execution plan, TrsDocRcvItem table costs 47%. Creating a index on TrsDocRcvItem table should help the query
CREATE NONCLUSTERED INDEX NIX_TrsDocRcvItem
ON [Trs].[TrsDocRcvItem] (AccOperationRef,ItemNum,HeaderRef)
INCLUDE (Amount)
Suggested index from the execution plan you have posted
CREATE NONCLUSTERED INDEX [<Name of Missing Index, sysname,>]
ON [Trs].[TrsDocRcvItem] ([AccOperationRef])
INCLUDE ([ItemNum],[Amount],[HeaderRef])

Answer 2

SELECT Vosol = ( CASE WHEN EXISTS ( SELECT Id
FROM trs.CollectionHeaderView AS chv
WHERE chv.ItemNum = itm.ItemNum
AND chv.CollectionType = '1' )
THEN ISNULL(itm.Amount, 0)
ELSE 0
END ) ,
Vakhast = ( CASE WHEN EXISTS ( SELECT Id
FROM trs.CollectionHeaderView AS chv
WHERE chv.ItemNum = itm.ItemNum
AND chv.CollectionType = '2' )
THEN ISNULL(itm.Amount, 0)
ELSE 0
END )
FROM trs.TrsDocRcvItem AS itm
INNER JOIN
(
SELECT * FROM trs.TrsDocRcvHeader
WHERE DocTypeRef NOT IN ( 1141, 1142, 1241, 1242 )
AND ( State = '1' OR State = '2' )
) hdr ON itm.HeaderRef = hdr.Id
LEFT JOIN acc.DL AS dl ON dl.Id = hdr.DLRef
LEFT JOIN trs.TrsDocType AS docType ON docType.Id = hdr.DocTypeRef
INNER JOIN sle.SleCustomer AS customer ON customer.DLRef = dl.Id
INNER JOIN
( SELECT * FROM trs.AccOperation WHERE StateType = '1'
) operation operation.Id = itm.AccOperationRef
You can replace
WHERE hdr.DocTypeRef NOT IN ( 1141, 1142, 1241, 1242 )
AND ( hdr.State = '1'
OR hdr.State = '2'
)
AND operation.StateType = '1'
To
INNER JOIN
(
SELECT * FROM trs.TrsDocRcvHeader
WHERE DocTypeRef NOT IN ( 1141, 1142, 1241, 1242 )
AND ( State = '1' OR State = '2' )
) hdr ON itm.HeaderRef = hdr.Id
INNER JOIN
( SELECT * FROM trs.AccOperation WHERE StateType = '1'
) operation operation.Id = itm.AccOperationRef
I hope that it will help you.