February 25, 2014 at 7:17 am
Hi all,
I just wonder why I see so much difference between durations within capureded trace-data??
I'd like to know how many time each application has spend during the time the trace was captured.
When I use the next script I see a big differances in values;
SELECT SUM(CPU) as cpu,--Amount of CPU time (in milliseconds) used by the event.
SUM(duration) as duration,--Amount of time (in milliseconds) taken by the event.
SUM(
CAST(DATEPART ( minute , endtime - starttime )*60000 +
DATEPART ( second , endtime - starttime )*1000+
DATEPART ( millisecond , endtime - starttime ) as int) ) as millisec
FROM << trace_table >>
where applicationname = '<< application_name >>'
cpu -- duration -- millisec
---------------------------------------
485302 --7685781173 --7687893
This trace ran for just 3 minutes !!!!
Can someone tell me which one is the one I'm looking for??
I'm aware that the SUM on all applications can be larger as the total trace-duration due to simultantious logins (or pooling).
Thanks in advance.
Regrads,
Guus
February 25, 2014 at 7:33 am
Duration is clock time. The amount of time elapsed between a query starting and a query completing. CPU time is the amount of time spent executing on the CPU, calculated per core.
Which you use depends on which you want. Interested in what's taking time, use duration. Interested in what uses CPU, use CPU.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
February 25, 2014 at 7:41 am
Gail,
Thanks for the explanation.
So - if I measure CPU = 150 running an 8-core server (maxdop 0) the total CPU will be 1200 ???
Guus
February 25, 2014 at 7:43 am
gkramer 23701 (2/25/2014)
So - if I measure CPU = 150 running an 8-core server (maxdop 0) the total CPU will be 1200
No, 150.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
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