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qwertyjjj
Posting Yak Master
131 Posts |
 Posted - 2007-10-15 : 10:19:19
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| Trying to find some guides on how to investigate trace data.I noticed a lot of queries with Reads but the duration was 0.Is this a cause for concern? Why would it be zero?Also, how many reads would you say is too many? I realise it's a bit subjective... |
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SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2007-10-15 : 10:21:57
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Very subjective.If you have DURATION is 0, but has plenty of READS, you have fast disk access!We have READS of 400,000 (DURATION 12,500) which we now think is minimal for that type of query. It was 8,000,000 (DURATION 122,000) before.
E 12°55'05.25"N 56°04'39.16" |
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qwertyjjj
Posting Yak Master
131 Posts |
Posted - 2007-10-15 : 10:30:52
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| Well, one trace starts running a load of sp_execute code.All reads say 3, duration 0, CPU 0. Obviously, it's not 0 because it starts at say 10:00:10 and finishes getting through all of them at 10:00:50.Whereas a proper SQL query like SELECT field1, field2 from table has about 600 reads and a duration of 3016Seems odd. |
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SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2007-10-15 : 10:37:08
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Have you tried all these four?SP:StmtCompletedSP:StmtStartingSQL:StmtCompletedSQL:StmtStarting
E 12°55'05.25"N 56°04'39.16" |
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evilDBA
Posting Yak Master
155 Posts |
Posted - 2007-10-15 : 11:59:42
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| Reads , recorded in SQL profiler, are LOGICAL reads, not PHYSICAL readsSo you can have many reads and Duration=0 |
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qwertyjjj
Posting Yak Master
131 Posts |
Posted - 2007-10-15 : 12:06:46
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| How would I find which trace entry corresponds to a DLookup from Access?I presume the JET engine would transform this over into SQL at some point?I just want to see if the DLookup is scanning en entire table and issuing multiple selects when it could all be done in 1 go. |
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Using profiler - what is too many reads / too long