Re: Autotuning Group Commit

1) I'm in favor of autotuning anything possible.
2) In addition to turning group_commit on and off, what about also
adjusting the commit delay, based on statistics of recent commits? It
might require a slightly larger sample set (maybe the last 100 commits),
but it seems it would provide more flexibility (hence more usefulness)
to the autotuning.

I belive you'd want to first calculate the elapsed time between each
commit in the sample set, then look for groupings of elapsed time. If
you have a set that looks like this:

Time (ms) Number
2 *
4 *
6
8 **
10 *
12 ******
14 ****
16 **
18
20 *

then you'd want a delay of 16ms. I think this calculation could be done
fairly quickly by grouping the commits into buckets of different elapsed
times, then look for the largest elapsed time that has a number of
commits greater than the mean number of commits for all the buckets. But
I'm not a statistician, hopefully someone here is. :)
--
Jim C. Nasby, Database Consultant decibel(at)decibel(dot)org
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