On 07/06/2018 12:34 PM, Robert Haas wrote:
On Fri, Jul 6, 2018 at 3:02 PM, Joshua D. Drake <j...@commandprompt.com> wrote:
Will stats, if we move toward the suggested changes be "less" accurate than
they are now? We already know that stats are generally not accurate but they
are close enough. If we move toward this change will it still be close
enough?
There proposed change would have no impact at all on the long-term
accuracy of the statistics. It would just mean that there would be
race conditions when reading them, so that for example you would be
more likely to see a count of heap scans that doesn't match the count
of index scans, because an update arrives in between when you read the
first value and when you read the second one. I don't see that
mattering a whole lot, TBH, but maybe I'm missing something.
I agree that it probably isn't a big deal. Generally speaking when we
look at stats it is to get an "idea" of what is going on. We don't care
if we are missing an increase/decrease of 20 of any particular value
within stats. Based on this and what Andres said, it seems like a net
win to me.
JD
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