Optimize SQL Query to avoid Hash Match (Aggregate)

Question

I have a SQL query that takes 7 minutes+ to return results. I'm trying to optimize as much as possible and the Execution plan loses 82% of the time on a Hash Match (Aggregate). I've done some searching and looks like using an "EXISTS" would help to resolve, but I haven't figured out the syntax of the query to make it work. Here's the query:

select dbo.Server.Name,
                dbo.DiskSpace.Drive,
                AVG(dbo.DiskSpace.FreeSpace) as 'Free Disk Space',
                AVG(dbo.Processor.PercentUsed) as 'CPU % Used',
                AVG(dbo.Memory.PercentUtilized) as '% Mem Used'

                from Server
                join dbo.DiskSpace on dbo.Server.ID=DiskSpace.ServerID
                join dbo.Processor on dbo.Server.ID=Processor.ServerID
                join dbo.Memory on dbo.Server.ID=dbo.Memory.ServerID

                where
                dbo.Processor.ProcessorNum='_Total' 
                    and dbo.Processor.Datetm>DATEADD(DAY,-(1),(CONVERT (date, GETDATE()))) 
                    and (      dbo.Server.Name='qp-ratking' 
                            or dbo.Server.Name='qp-hyper2012' 
                            or dbo.Server.Name='qp-hyped' 
                            or dbo.Server.Name='qp-lichking')
                Group By dbo.server.name, Dbo.DiskSpace.Drive
                Order By Dbo.Server.Name, dbo.DiskSpace.Drive;

How do I reduce/eliminate the joins using EXISTS? Or if there is a better way to optimize, I'm up for that too. Thanks

Answer 1

A co-worker broke down the query and pulled out data in smaller chunks so there wasn't as much processing of the data returned by the joins. It cut it down to less than 1 second return. New Query:

WITH tempDiskSpace AS
(
SELECT dbo.Server.Name
      ,dbo.DiskSpace.Drive
      ,AVG(dbo.DiskSpace.FreeSpace) AS 'Free Disk Space'

FROM dbo.DiskSpace
      LEFT JOIN dbo.Server ON dbo.DiskSpace.ServerID=Server.ID

WHERE dbo.DiskSpace.Datetm>DATEADD(DAY,-(1),(CONVERT (date, GETDATE())))
AND (dbo.Server.Name='qp-ratking'
      OR dbo.Server.Name='qp-hyper2012'
      OR dbo.Server.Name='qp-hyped'
      OR dbo.Server.Name='qp-lichking')

GROUP BY Name, Drive
)
,tempProcessor
AS
(
SELECT dbo.Server.Name
      ,AVG(dbo.Processor.PercentUsed) AS 'CPU % Used'

FROM dbo.Processor
      LEFT JOIN dbo.Server ON dbo.Processor.ServerID=Server.ID

WHERE dbo.Processor.Datetm>DATEADD(DAY,-(1),(CONVERT (date, GETDATE())))
AND dbo.Processor.ProcessorNum='_Total'
AND (dbo.Server.Name='qp-ratking'
      OR dbo.Server.Name='qp-hyper2012'
      OR dbo.Server.Name='qp-hyped'
      OR dbo.Server.Name='qp-lichking')

GROUP BY Name
)
,tempMemory
AS
(
SELECT dbo.Server.Name
      ,AVG(dbo.Memory.PercentUtilized) as '% Mem Used'

FROM dbo.Memory
      LEFT JOIN dbo.Server ON dbo.Memory.ServerID=Server.ID

WHERE dbo.Memory.Datetm>DATEADD(DAY,-(1),(CONVERT (date, GETDATE())))
AND (dbo.Server.Name='qp-ratking'
      OR dbo.Server.Name='qp-hyper2012'
      OR dbo.Server.Name='qp-hyped'
      OR dbo.Server.Name='qp-lichking')

GROUP BY Name
)

SELECT tempDiskSpace.Name, tempDiskSpace.Drive, tempDiskSpace.[Free Disk Space], tempProcessor.[CPU % Used], tempMemory.[% Mem Used]
FROM tempDiskSpace
LEFT JOIN tempProcessor ON tempDiskSpace.Name=tempProcessor.Name
LEFT JOIN tempMemory ON tempDiskSpace.Name=tempMemory.Name
ORDER BY Name, Drive;

Thanks for all the suggestions.