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SQL Server 2005
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SQL Server 2005 Performance Tuning
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Server Comparison
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Andrew Hartnett
Andrew Hartnett
Posted Friday, March 13, 2009 8:09 AM
Forum Newbie
Group: General Forum Members
Last Login: Tuesday, May 10, 2011 1:38 PM
Points: 2,
Visits: 108
This is my first post on here so bare with me. I have a sql query that I have run on two different servers. I am trying to get some performance metrics so I can see which server has a better architecture. The only thing that I do not understand is that the TEST server has a smaller elapsed time but has a longer CPU seconds/Iteration Avg. It would seem to me that if the cpu time is longer that the elapsed time would follow the same trend. Any ideas as to why this is would be helpful. Thanks
Server TEST BISQL
Client Seconds/Iteration(Avg): 14.4086 17.6521
CPU Seconds/Iteration (Avg): 62.8717 37.0128
Actual Seconds/Iteration: 14.4101 17.6065
Logical Reads/Iterations (Avg) 4507028 4507138
Elapsed Time 00:24:01.224 00:29:26.779
Post #675195
Henry Treftz
Henry Treftz
Posted Friday, March 13, 2009 9:04 AM
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Group: General Forum Members
Last Login: Monday, May 06, 2013 1:51 PM
Points: 175,
Visits: 327
CPU time is not the only metric, don't forget I/O as well. Have you tried looking at the actual query plan (not the estimated one) for the query on each server? If so is there a difference?
Post #675285
Andrew Hartnett
Andrew Hartnett
Posted Friday, March 13, 2009 10:06 AM
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Last Login: Tuesday, May 10, 2011 1:38 PM
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The query plans are indeed different. The actual plan on TEST has a nested loop, an index scan and a key lookup. The actual plan on BISQL parallelism and a table scan. So the reason for the longer elapsed time with the shorter cpu time might be I/O? They both produce the same amount of records
Post #675368
Grant Fritchey
Grant Fritchey
Posted Friday, March 13, 2009 10:30 AM
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Group: General Forum Members
Last Login: Today @ 3:04 PM
Points: 13,375,
Visits: 25,159
If it's two different plans, that's probably the issue.
Make sure the same parameters are in use on both and make sure that both have updated statistics and defragmented indexes.
The very best way to compare apples to apples is to restore a backup from the first server on the second. That'll let you be sure that you have a precise copy of the data, the structures, statistics, indexes, etc. Then, any differences are likely to be caused by hardware; memory, cpu or disk.
----------------------------------------------------
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood..." Theodore Roosevelt
The Scary DBA
Author of:
SQL Server 2012 Query Performance Tuning
SQL Server 2008 Query Performance Tuning Distilled
and
SQL Server Execution Plans
Product Evangelist for
Red Gate Software
Post #675394
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