Monday, September 30, 2013

Easy Trace File Query

Whenever a customer has an issue with slowness, we request a trace file to help us figure out where the problem may be. The trace allows us to see which procs are called most often, and which are taking up the most time.

I used to import the trace file into a temporary table, then run my own queries on the file to pinpoint issues. While that works well, it requires me to make additional copies of the customer's data which all has to be tracked due to in-house security rules. Since I don't like having to do excessive paperwork, I found a way to easily read in the data from where it sits rather than importing it into SQL server:

Select ObjectName
, substring(DatabaseName, 1, 18) as dbname
AVG(cpu) as cpuuse
, AVG(reads) as avgreads
, AVG(writes) as avgwrites
, COUNT(EndTime) as instances
, AVG(duration) as avgduration
, COUNT(EndTime) * AVG(reads) as cumexpense
from fn_trace_gettable ('C:\Temp\MyTraceFile.trc', DEFAULT)
group by ObjectName, substring(DatabaseName, 1, 18)
order by avgreads desc

The above query orders the items in the trace by average number of reads. Next, order the list by Average CPU then Average Duration. Any queries that are consistently at the top of the list are the first candidates for tuning.

I've also used the following to zero in on data regarding specific procs:

select  DatabaseName, ObjectName, TextData, CPU, Reads, Writes
from fn_trace_gettable ('C:\Temp\MyTraceFile.trc', DEFAULT)
where ObjectName ='MyStoredProc' or ObjectName='YourStoredProc'

Have fun analyzing your trace files.

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