> It would be also interesting if "reads" exposed in various places (isql,
> monitoring tables, trace api) are pure physical reads from disk and/or
> fetched from the OS file system cache.
>
> I guess, it could be also from the file system cache, because I've seen
> situations where execution time is larger for the same number of
> physical reads for a newly established connection, which then decreases
> for sub-sequent execution of the same statement with an equal number of
> reads.
There is no way to know if OS resolved read request from cache or from
disk.
Even if application is used so called "direct IO" read request could be
resolved
from file cache - if some other application reads same file using file cache
few
moments before.
Regards,
Vlad
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