can lot of CASTs/Union or ISNULL possibly cause blocks?

This query runs fine every day scheduled.. but yesterday, it was blocked by itself in sysprocesses.. when I did select * from master..sysprocesses where blocked<>0 I saw 12 lines all for this one process running this, and all with same spid and same blocked column data.

is it because of excessive UNION/CAST etc. CAn you suggest?
LVL 5
25112Asked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

25112Author Commented:
The actual processing is from stored proc.. but I put it as code format by substituting the parameter values here to illustrate, any thoughts on making this code efficient to avoid blocks/locks?

 ~~~~~~~~~~~~~~~~~~~~~~
SET NOCOUNT ON        
        
DECLARE @JobYear varchar(4)          
SET @JobYear = '2004'        
DECLARE @PairedID char(3)          
SET @PairedID = '113'         
        
        
DECLARE @ExtractDt datetime        
SET @ExtractDt = (Select Distinct Max(dbo.PASNote.ExtractDt)         
   From dbo.PASNote         
   Where dbo.PASNote.JobYear = @JobYear)        
        
DECLARE @PPExtractDate datetime        
SET @PPExtractDate = (Select Distinct  PPExtractDate        
   From dbo.PASNote         
   Where dbo.PASNote.JobYear = @JobYear        
               And ExtractDt = @ExtractDt)        
          
 Select         
 CAST(@JobYear as char(4))         
        + '-'        
        + CAST(@JobYear+1 as char(4)) As [JobYear],        
 CAST([PairID] as int) As [FinalizedPair],        
          CAST([BCPERName] as varchar(60)) As [FinalizedBCPER],        
        CAST([UCANName] as varchar(30)) As [FinalizedUCAN],        
        CAST((SUBSTRING(Cast([PairID] as char),1,1) + '-'        
         + SUBSTRING(Cast([PairID] as char),2,2) + '-'        
          + SUBSTRING(Cast([PairID] as char),4,2) + '-'        
           + SUBSTRING(Cast([PairID] as char),6,3) + '-'        
          + SUBSTRING(Cast([PairID] as char),9,1)) as varchar(30)) As [mtPair],        
        CAST(TempTable.[PickID] as varchar(4)) PickID,        
        CASE WHEN TempTable.[PickID]  IN('J2','J3','J4','J5','J6') THEN 'J2'        
                    WHEN TempTable.[PickID]  IN('M2','M3') THEN 'M2'           
                    ELSE  TempTable.[PickID]   END AS  [PickGroupCd],        
 CAST(' ' as varchar(60)) As [RegulatingNUA],        
        CAST(' ' as varchar(30)) As [SchedProgramCd],        
 CAST(' ' as varchar(30)) As [SchedIdCd],        
CAST(' ' AS VARCHAR(5)) AS [LeadStatusCd],        
CAST(' ' AS VARCHAR(5)) AS [PLKStatusCd],        
 CAST(0 as smallint) As [PeakedCap],        
 CAST(0 as int) As [Accumul],        
        CAST(0 as decimal(18,3)) As [PeakedMDT],        
 CAST(0 as decimal(18,5)) As [PaceAdj],        
        CAST(0  as dec(13,0)) as [PrePHCstDst],        
 CAST(0  as dec(13,3)) as [PrePHMDT],        
 CAST(0  as dec(13,0)) as [PrePTCstDst],        
 CAST(0  as dec(13,3)) as [PrePTMDT],         
        CAST(0  as dec(13,0)) as [PeakedPHForCstDst],        
        CAST(0  as dec(13,3)) as [PeakedPHForMDT],        
        CAST(0  as dec(13,0)) as [PeakedPTForCstDst],        
        CAST(0  as dec(13,3)) as [PeakedPTForMDT],        
 CAST(0  as dec(13,0)) as [PHJustForCstDst],        
 CAST(0  as dec(13,3)) as [PHJustForMDT],        
 CAST(0  as dec(13,0)) as [PTJustForCstDst],        
 CAST(0  as dec(13,3)) as [PTJustForMDT],        
 CAST(0  as dec(13,0)) as [PHPunchCstDst],        
 CAST(0  as dec(13,3)) as [PHPunchMDT],        
 CAST(0  as dec(13,0)) as [PTPunchCstDst],        
 CAST(0  as dec(13,3)) as [PTPunchMDT],        
 CAST(0  as dec(13,0)) as [BaseCstDst],        
 CAST(0  as dec(13,3)) as [BaseMDT],        
 CAST(0  as dec(13,0)) as [AdvCstDst],        
 CAST(0  as dec(13,3)) as [AdvMDT],        
        CAST([UCANName] as varchar(30)) AS [UCANName],        
        Cast(@ExtractDt As datetime) As [ExtractDt],        
        Cast(@PPExtractDate as datetime) AS [PPExtractDate]        
 FROM  dbo.CI_NUA         
        INNER JOIN         
        (SELECT CAST('DX' AS VARCHAR(10)) AS [NUACTGY],        
       CAST(TBLSC.[PickID] AS VARCHAR(4)) PickID        
       FROM        
       (SELECT CAST('A1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('A2' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('A3' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('B1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('C1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('D1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('D2' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('E1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('E2' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('F1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('G1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('H1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('I1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('J1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('K1' AS VARCHAR(4)) PickID        
 UNION ALL        
       SELECT CAST('L1' AS VARCHAR(4)) PickID        
       UNION ALL        
  SELECT CAST('L2' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('M1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('N1' AS VARCHAR(4)) PickID        
       UNION ALL        
       SELECT CAST('O1' AS VARCHAR(4)) PickID        
     ) AS TBLSC        
       ) AS TempTable        
       ON dbo.CI_NUA.[BCPERAbbr] = TempTable.[NUACTGY]        
       AND dbo.CI_NUA.[JobYearFK] = @JobYear        
        WHERE [BCPERAbbr] = 'DX' AND PairID = @PairedID        
        AND TempTable.[PickID] NOT IN        
        (SELECT DISTINCT [ReportPickID]        
                FROM dbo.PASNote         
                WHERE GroupPair = @PairedID AND ExtractDt = @ExtractDt      
                AND [JobYear] = @JobYear)        
--         
--        
Union All          
--        
-- Select Note report lines from table dbo.PASNote         
--        
 Select         
 CAST(JobYear as char(4)) + '-' +        
        CAST((CAST(JobYear as dec(4,0)) + 1) as char(4)) As [JobYear],        
 CAST(GroupPair as int) As [FinalizedPair],        
        CAST(NUA.[BCPERName] as varchar(60)) As [FinalizedBCPER],        
        CAST(NUA.[UCANName] as varchar(30)) As [FinalizedUCAN],        
        CAST((SUBSTRING(Cast([GroupPair] as char),1,1) + '-'        
         + SUBSTRING(Cast([GroupPair] as char),2,2) + '-'        
          + SUBSTRING(Cast([GroupPair] as char),4,2) + '-'        
           + SUBSTRING(Cast([GroupPair] as char),6,3) + '-'        
          + SUBSTRING(Cast([GroupPair] as char),9,1)) as varchar(30)) As [mtPair],        
        CAST(ReportPickID as varchar(4)) PickID,        
        CASE WHEN ReportPickID  IN('J2','J3','J4','J5','J6') THEN 'J2'        
                    WHEN ReportPickID  IN('M2','M3') THEN 'M2'        
                    ELSE  ReportPickID   END AS  [PickGroupCd],        
 CAST(RegulatingBCPERName as varchar(60)) As [RegulatingNUA],        
        CAST(IsNull(SchedProgramCd,' ') as varchar(30)) As [SchedProgramCd],        
 CAST(IsNull(SchedIdCd,' ') as varchar(30)) As [SchedIdCd],        
    CAST([LeadStatusCd] AS VARCHAR(5)) AS [LeadStatusCd],        
CAST([PLKStatusCd] AS VARCHAR(5)) AS [PLKStatusCd],        
 CAST(IsNull(PeakedCap,0) as smallint) As [PeakedCap],        
 CAST(IsNull(Accumul,0) as int) As [Accumul],        
        CAST(IsNull(PeakedMDT1,0) as decimal(18,3)) As [PeakedMDT],        
 CAST(IsNull(DistrictPaceAdj,0) as decimal(18,5)) As [PaceAdj],        
        CAST(IsNull(PrePHCstDst,0)  as dec(13,0)) as [PrePHCstDst],        
 CAST(IsNull(PrePHMDT,0)  as dec(13,3)) as [PrePHMDT],        
 CAST(IsNull(PrePTCstDst,0)  as dec(13,0)) as [PrePTCstDst],        
 CAST(IsNull(PrePTMDT,0)  as dec(13,3)) as [PrePTMDT],         
        CAST((CAST(IsNull(PHJustForCstDst,0)  as dec(13,0)) + CAST(IsNull(PHPunchCstDst,0)  as dec(13,0)))  as dec(13,0)) as [PeakedPHForCstDst],        
        CAST((CAST(IsNull(PHJustForMDT,0)  as dec(13,3)) + CAST(IsNull(PHPunchMDT,0)  as dec(13,3)))  as dec(13,3)) as [PeakedPHForMDT],        
        CAST((CAST(IsNull(PTJustForCstDst,0)  as dec(13,0)) + CAST(IsNull(PTPunchCstDst,0)  as dec(13,0)))  as dec(13,0)) as [PeakedPTForCstDst],        
        CAST((CAST(IsNull(PTJustForMDT,0)  as dec(13,3)) + CAST(IsNull(PTPunchMDT,0)  as dec(13,3)))  as dec(13,3)) as [PeakedPTForMDT],        
 CAST(IsNull(PHJustForCstDst,0)  as dec(13,0)) as [PHJustForCstDst],        
 CAST(IsNull(PHJustForMDT,0)  as dec(13,3)) as [PHJustForMDT],        
 CAST(IsNull(PTJustForCstDst,0)  as dec(13,0)) as [PTJustForCstDst],        
 CAST(IsNull(PTJustForMDT,0)  as dec(13,3)) as [PTJustForMDT],        
 CAST(IsNull(PHPunchCstDst,0)  as dec(13,0)) as [PHPunchCstDst],        
 CAST(IsNull(PHPunchMDT,0)  as dec(13,3)) as [PHPunchMDT],        
 CAST(IsNull(PTPunchCstDst,0)  as dec(13,0)) as [PTPunchCstDst],        
 CAST(IsNull(PTPunchMDT,0)  as dec(13,3)) as [PTPunchMDT],        
 CAST(IsNull(BaseCstDst,0)  as dec(13,0)) as [BaseCstDst],        
 CAST(IsNull(BaseMDT,0)  as dec(13,3)) as [BaseMDT],        
 CAST(IsNull(AdvCstDst,0)  as dec(13,0)) as [AdvCstDst],        
 CAST(IsNull(AdvMDT,0)  as dec(13,3)) as [AdvMDT],        
      CAST(NUA.UCANName as varchar(30)) AS [UCANName],        
        Cast(ExtractDt As datetime) As [ExtractDt],        
        Cast(PPExtractDate As datetime) As [PPExtractDate]        
 FROM  dbo.PASNote         
        Inner Join dbo.CI_NUA NUA        
        On dbo.PASNote.GroupPair = NUA.PairID        
        AND NUA.[JobYearFK] = @JobYear        
        WHERE        
        JobYear = @JobYear and      
        GroupPair = @PairedID AND        
        ExtractDt = @ExtractDt        
   
 Order by FinalizedPair,         
                 PickID,RegulatingNUA,        
                 PeakedCap,SchedIdCd         
        
SET NOCOUNT OFF

Open in new window

0
Vitor MontalvãoMSSQL Senior EngineerCommented:
What causes locks are long running queries. How long usually this query takes to run?
0
25112Author Commented:
right now it just ran in 3 seconds..  it has run scheduled for many months.. it was just yesterday that this has misbehaved (that we saw)..

what was puzzling was generally in sysprocesses, the blocked id is different than spid.. but here spid was same as blocked id and also several lines...
0
Get your problem seen by more experts

Be seen. Boost your question’s priority for more expert views and faster solutions

Vitor MontalvãoMSSQL Senior EngineerCommented:
Maybe was a single time issue. I recommend you to let it be and keep an eye on the process to see if will happen again.
0
PortletPaulfreelancerCommented:
Just a small observation,

      SELECT DISTINCT
            MAX(dbo.PASNote.ExtractDt)
      FROM dbo.PASNote
      WHERE dbo.PASNote.JobYear = @JobYear


There is only a single value returned, so "distinct" is completely redundant in such circumstances.
"select distinct": use it sparingly because it is the enemy of performance.
0
25112Author Commented:
thank you. I will keep an eye on it.

Paul, appreciate your note.

do you have an mock tsql example to show how bad performance can deteriorate by adding a distinct?
0
PortletPaulfreelancerCommented:
do you have an mock tsql example to show how bad performance can deteriorate by adding a distinct?
No. (And note, the impact would probably not be measurable in the query above. )

I raise it so you will be more aware of the implications it brings; it can be horrible. Literally horrible.


I do have an article on Distinct: Select Distinct is returning duplicates (Look for "Hail Mary..." in particular)
and in the references: Why I Hate DISTINCT
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Microsoft SQL Server 2008

From novice to tech pro — start learning today.