G
George Potemkin
Guest
Fact: duration at least of MTX latch locks may significantly vary depending from the external factors like a failure of disk in RAID or long queues of processes on OS level. "Significantly" = by millions (mayby billions) times. Number of latch locks/naps will be low during such extreme cases. I don't know if there are the situations where the duration of latch locks are only moderately increasing above normal - let's say, by tens/hundreds times. IMHO, the only way to see such situations is a latch timing. I would enable latch timing collection in the tests without competions for resources in shared memory - with only one session running. Just to estimate a percent of time the session locks resources compared to the total execution time. It will give an estimation how many processes can be run simulatiosly before the competion will become a bottleneck.
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