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  • Table Scan - Aggregate Cost Structure

    In the previous post, I mention that in an earlier post on IO cost structure, that the cost of a table scan was approximately 1 CPU-micro sec per page, plus approximately 0.05 us per row for just a SELECT COUNT(*) This was calibrated on a 2-way Xeon 5430 Quad-Core 2.66GHz. I should also add that the test tables have a clustered primary key, with ...
    Posted to Joe Chang (Weblog) by jchang on February 27, 2009
  • IO Cost Structure – Anticipating SSD arrays

    An observant person has probably noticed that SQL queries requiring disk reads not only have longer duration but also higher CPU times. It is not hard then to deduce that disk access (for both HDD and SSD), which involves the OS performing an IO call, the SQL Server process finding a place in the buffer cache for the data pages, and possibly ...
    Posted to Joe Chang (Weblog) by jchang on September 4, 2008
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