June 14, 2011 at 9:14 am
I heard the reads column in profiler is the Number of logical read I/Os.
So how does that relate to Disk sec/reads?
For example
1)in my fantasy DB where a query/session has 10,000.000 reads and hardly any CPU writes etc.
2)I have an average Disk sec/reads of 0.02 for the period
3)So my execution time is (10,000,000*0.02)/60 = 3333 seconds?
So if my disk/reads where 0.01 the execution time would be 1666?
Is this completely rubbish?
June 14, 2011 at 10:37 am
I wouldn't get too hung on trying to correlate the two, but the events are showing pages read. A 1 is one page. 2, etc. are more pages. I don't know that the Disk Reads/sec is pages, although I think it is. But it's going to include OS pages, tempdb, all kinds of stuff that you're not going to see directly in a given RPC:Complete set of reads, so getting a direct correlation could make you nuts.
----------------------------------------------------The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood... Theodore RooseveltThe Scary DBAAuthor of: SQL Server 2017 Query Performance Tuning, 5th Edition and SQL Server Execution Plans, 3rd EditionProduct Evangelist for Red Gate Software
June 15, 2011 at 2:23 am
Thanks was just trying to get some mental representation of what difference Disk sec/reads makes apart from the usual 0.02 is poor
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