Question

I have a set with data in a SQL Server database and I need to calculate uptime of a machine. I’m using two variables to determine uptime or downtime. These two variables are machine_ON and failure(s). machine_ON is only one variable in the database, failure can be 64 different failures, but all indicates as fx_x.

The status information of these variables is stored in the database as follow:

timestamp                   failurebitNr    timestampOutOfAlarm
2012-01-17 10:38:58.000     f1_14           2012-01-17 10:39:05.000

Meaning: failure f1_14 was active from 2012-01-17 10:38:58.000 until 2012-01-17 10:39:05.000

Also the machine_ON state is saved in the same table on the same way, only the failurebitNr has a different value [t2_13].

So to determine the uptime, I need to get the timediff between timestamp and timestampOutOfAlarm where failurebutNr = 't2_13' minus any failure time.

So for example I have those rows in my database:

This should give the following graphical representation:

Green is uptime, red is downtime.

I’m used to work with PHP and than use a while loop and file some array’s and do other scripting. But now I need to do this all in a SQL Server database in query ways…

So, how can I calculate the uptime (green) and downtime (red)?

UPDATE

I’ve tried to get the time in seconds that the machine is ON. I used this query:

<!-- language: lang-sql -->
DECLARE @startDate datetime
DECLARE @endDate datetime
DECLARE @projectNr int
DECLARE @MachineNr nvarchar(10) 

SET @startDate = '2012-01-01 00:00:00.000'
SET @endDate  = '2012-02-01 00:00:00.000'
SET @projectNr = '1234567'
SET @MachineNr = '2'

SELECT 
    DATEDIFF("SECOND",
        CASE WHEN timestamp < @startDate 
            THEN @startDate 
            ELSE timestamp 
        END, 
        CASE WHEN timestampOutOfAlarm > @endDate OR timestampOutOfAlarm IS NULL 
            THEN @endDate
            ELSE timestampOutOfAlarm 
        END) AS Uptime
FROM 
    [table]
WHERE
     timestamp < @endDate
     AND (timestampOutOfAlarm > @startDate OR timestampOutOfAlarm IS NULL)
     AND fileProjectNr = @projectNr
     AND fileProjectMachineNr = @MachineNr
     AND (failureBitNr = 't2_13' AND failureBitValue = '1')

Answer 1

Problem solved:

I did it in 2 stored procedures, or Query’s. One for getting the “ON” time and one for getting all the “DOWN” time within the “ON” time. Whith those two times I can calculate the uptime, downtime, maintenance time.

Query for ON time:

<!-- language: lang-sql -->
SELECT  fctAlarmId,
        fileProjectNr, 
        fileProjectMachineNr, 
        failureBitNr,   
        timestamp, 
        CASE WHEN timestampOutOfAlarm > @endDate OR timestampOutOfAlarm IS NULL 
            THEN @endDate
            ELSE timestampOutOfAlarm
        END 
        AS timestampOutOfAlarm
INTO    #tempTable1
FROM    fctAlarmHistory
WHERE   (timestampOutOfAlarm >= @startDate OR timestampOutOfAlarm = NULL) 
        AND timestamp < @endDate
        AND failureBitValue = 1 
        AND failureBitNr = 't2_13'
        AND fileProjectNr = @projectNr
        And fileProjectMachineNr = @ProjectMachineNr

-- SUM the result of all ON times into OnTime in seconds
SELECT 
    SUM(DATEDIFF("SECOND",
        CASE WHEN timestamp < @startDate 
            THEN @startDate 
            ELSE timestamp 
        END, 
        CASE WHEN timestampOutOfAlarm > @endDate
            THEN @endDate 
            ELSE timestampOutOfAlarm 
        END)) AS OnTime
FROM
    #tempTable1

Query for Downtime during ON time:

<!-- language: lang-sql -->
SELECT  fctAlarmId,
        fileProjectNr, 
        fileProjectMachineNr, 
        failureBitNr,   
        timestamp, 
        CASE WHEN timestampOutOfAlarm > @endDate OR timestampOutOfAlarm IS NULL 
            THEN @endDate
            ELSE timestampOutOfAlarm
        END 
        AS timestampOutOfAlarm
INTO    #tempTable1
FROM    fctAlarmHistory
WHERE   (timestampOutOfAlarm >= @startDate OR timestampOutOfAlarm = NULL) 
        AND timestamp < @endDate
        AND failureBitValue = 1 
        AND failureBitNr = 't2_13'
        AND fileProjectNr = @projectNr
        And fileProjectMachineNr = @ProjectMachineNr

SELECT  fctAlarmId,
        fileProjectNr, 
        fileProjectMachineNr, 
        failureBitNr,   
        timestamp, 
        CASE WHEN timestampOutOfAlarm > @endDate OR timestampOutOfAlarm IS NULL 
            THEN @endDate
            ELSE timestampOutOfAlarm
        END 
        AS timestampOutOfAlarm
INTO    #tempTable2
FROM    fctAlarmHistory
WHERE   (timestamp BETWEEN @startDate AND @endDate) 
        AND failureBitValue = 1
        AND (failureBitNr LIKE'f%')
        AND fileProjectNr = @projectNr
        And fileProjectMachineNr = @ProjectMachineNr

CREATE TABLE #tempTable3
(
ID int IDENTITY(1,1),
timestamp datetime,
timestampOutOfAlarm datetime
)

DECLARE failure_Cursor CURSOR FOR
SELECT timestamp, timestampOutOfAlarm
FROM #tempTable2
ORDER BY timestamp ASC

OPEN failure_Cursor

-- Perform the first fetch.
FETCH NEXT FROM failure_Cursor
INTO @rij_timestamp, @rij_timestampOutOfAlarm

INSERT INTO #tempTable3 (timestamp, timestampOutOfAlarm) VALUES(@rij_timestamp,@rij_timestampOutOfAlarm)

-- Check @@FETCH_STATUS to see if there are any more rows to fetch.
WHILE @@FETCH_STATUS = 0
    BEGIN
        PRINT @rij_timestamp
        IF @rij_timestamp <= (SELECT TOP 1 timestampOutOfAlarm FROM #tempTable3 ORDER BY timestamp DESC)
        BEGIN   
            IF @rij_timestampOutOfAlarm > (SELECT TOP 1 timestampOutOfAlarm FROM #tempTable3 ORDER BY timestamp DESC)
            BEGIN
                UPDATE #tempTable3 SET timestampOutOfAlarm = @rij_timestampOutOfAlarm WHERE ID = (SELECT TOP 1 ID FROM #tempTable3 ORDER BY timestamp DESC)

            END
        END
        ELSE
            INSERT INTO #tempTable3 (timestamp, timestampOutOfAlarm) VALUES(@rij_timestamp,@rij_timestampOutOfAlarm)

        FETCH NEXT FROM failure_Cursor
        INTO @rij_timestamp, @rij_timestampOutOfAlarm
    END
CLOSE failure_Cursor
DEALLOCATE failure_Cursor

-- Select the failure time.
SELECT 
    SUM(DATEDIFF("SECOND",
        CASE WHEN tt3.timestamp < @startDate 
            THEN @startDate 
            ELSE tt3.timestamp 
        END, 
        CASE WHEN tt3.timestampOutOfAlarm > tt1.timestampOutOfAlarm 
            THEN tt1.timestampOutOfAlarm 
            ELSE tt3.timestampOutOfAlarm 
        END)) AS DownTime
FROM
    #tempTable3 tt3
INNER JOIN
    #tempTable1 tt1
ON
    tt3.timestamp BETWEEN tt1.timestamp AND tt1.timestampOutOfAlarm