As per explaination given on MSDN at link http://msdn.microsoft.com/en-us/library/ms177648.aspx I am not able to understand the meaning of Reads and Writes fully.whether it is physical or logical or database Reads and Writes. Please help me out in this regards
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1There is a `logical_reads` column in there as well... – Martin Smith Oct 03 '11 at 07:50
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yes. That I know. But my question is about 'Reads' and 'Writes'. – Ganeshkumar Oct 03 '11 at 07:53
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2Well `reads` isn't going to mean logical reads though is it as there is already a column for that. All writes are logical, they get written to disc by the checkpoint, lazy writer processes etc. later. – Martin Smith Oct 03 '11 at 07:56
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thats the my question. What is it?. What that 'reads' and 'writes' signifies. Tell me about that. – Ganeshkumar Oct 03 '11 at 08:03
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It's number of physical reads/writes of 8k blocks. So if you multiply it by 8 you will get number of kilobytes that was read/written.
sha
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Martin answered your question...the logical_reads column corresponds to logical reads (i.e. requests that can be fulfilled by data currently available in the buffer cache) while reads corresponds to physical reads (i.e. requests for data that isn't currently in the buffer cache and requires a read from the relevant data file on disk).
A write in SQL Server modifies the page in memory; modified pages are marked as dirty and written to disk by asynchronous processes (also what Martin said).
Just to add, all of these figures represent number of pages, not rows.
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