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sys.dm_exec_requests read vs logical_reads columns

Posted on 2010-09-05
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If we  looked at sys.dm_exec_requests dmv, can someone tell me what the difference on read,writes and logical_reads column ?
Is that means logical_reads are reads from memory whereas reads are read from disk and write are write to disk ?
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Question by:motioneye
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by:Raja Jegan R
ID: 33609097
>> Is that means logical_reads are reads from memory whereas reads are read from disk and write are write to disk ?

Yes, Logical reads are the ones read from Memory - Buffer cache to be exact.
And Reads are from Physical Disk or MDF or Data File.

And Logical Writes are the ones done to LDF or log files and the Writes are the ones done to MDF or data file.
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by:Scott Pletcher
ID: 33628624
>> And Logical Writes are the ones done to LDF or log files and the Writes are the ones done to MDF or data file. <<

Are you sure about that?

I thought Logical Writes are those done to buffers (i.e., in memory only), and presumaby Writes are physical writes.
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Raja Jegan R earned 500 total points
ID: 33634050
>> I thought Logical Writes are those done to buffers (i.e., in memory only), and presumaby Writes are physical writes.

Yes, got confused and thanks for correcting it..

From BOL:
"A logical write occurs when data is modified in a page in the buffer cache. A physical write occurs when the page is written from the buffer cache to disk."
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