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Editorial Team
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Asked: 2026-06-13T11:54:33+00:00

I have a table with devices, and a second table with performance counters. So

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I have a table with devices, and a second table with performance counters. So I have device A which has lets say 1000 entries in the performance counters table. I am trying to get all the devices, 2500 of them, and their most recent performance counter. I have used an Outer Apply, which does accomplish the desired results, but the query takes 5 minutes to execute.

Is this the best way to get the info I am looking for or is there a better way? Is the performance of this query normal, and I am just asking too much? I am thinking of creating a third ‘temp’ table nightly that will hold this data so I can display and query the info quickly. What are the best practices for something like this?

Here is my current query:

   select * from Device D
      OUTER APPLY
          ( select top 1 *
              FROM PerformanceCounterValues
              where instance_id = D.pkid
              order by collection_time desc
           ) as tbl2

—– Solved —-

Here is my final actual query, and it works in 0 seconds. 

SELECT pkid, D.IDDevice, D.IDHardware, H.IDRecorder, D.Name, D.Description, H.Name as HardwareName, H.URI, R.HostName, R.Name as RecorderInstance, tbl2.collection_time, tbl2.raw_value, tbl2.calculated_value
  FROM [Surveillance].[dbo].[PerformanceCounterInstance] PCI
  JOIN [Surveillance].[dbo].[Devices] D on D.IDDevice = (SELECT REPLACE(STUFF([instance_name],1,CHARINDEX('[',[instance_name]),''),']',''))
  JOIN [Surveillance].[dbo].[Hardware] H on H.IDHardware = D.IDHardware
  JOIN [Surveillance].[dbo].[Recorders] R on R.IDRecorder = H.IDRecorder
    OUTER APPLY
    ( select top 1 *
        FROM [Surveillance].[dbo].[PerformanceCounterValue]
        where instance_id = PCI.pkid
        order by collection_time desc
        ) as tbl2
  where category_name = 'VideoOS Recording Server Device Storage'
  and D.Enabled = 1

It was just setting up the index that made the speed increase.

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1 Answer

  1. Editorial Team

    Enabled Index and used this query:

    SELECT pkid, D.IDDevice, D.IDHardware, H.IDRecorder, D.Name, D.Description, H.Name as HardwareName, H.URI, R.HostName, R.Name as RecorderInstance, tbl2.collection_time, tbl2.raw_value, tbl2.calculated_value
  FROM [Surveillance].[dbo].[PerformanceCounterInstance] PCI
  JOIN [Surveillance].[dbo].[Devices] D on D.IDDevice = (SELECT REPLACE(STUFF([instance_name],1,CHARINDEX('[',[instance_name]),''),']',''))
  JOIN [Surveillance].[dbo].[Hardware] H on H.IDHardware = D.IDHardware
  JOIN [Surveillance].[dbo].[Recorders] R on R.IDRecorder = H.IDRecorder
    OUTER APPLY
    ( select top 1 *
        FROM [Surveillance].[dbo].[PerformanceCounterValue]
        where instance_id = PCI.pkid
        order by collection_time desc
        ) as tbl2
  where category_name = 'VideoOS Recording Server Device Storage'
  and D.Enabled = 1
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