Re: Potential autovacuum optimization: new tables

On Sat, Oct 13, 2012 at 12:49 PM, Joshua Berkus <josh(at)agliodbs(dot)com> wrote:
>
> So, problem #1 is coming up with a mathematical formula. My initial target values are in terms of # of rows in the table vs. # of writes before analyze is triggered:
>
> 1 : 3
> 10 : 5
> 100 : 10
> 1000 : 100
> 100000 : 2000
> 1000000 : 5000
> 10000000 : 25000
> 100000000 : 100000
>
> .... etc. So problem #1 is a mathematical formula which gives this kind of curve. I've tried some solution-seeking software, but I don't know how to use it well enough to get something useful.

That is close to a power law, where best fit is about "threshold = 1.5
* (rows ** 0.6)"

rows yours powerfit
1.00E+00 3.00E+00 1.50E+00
1.00E+01 5.00E+00 5.97E+00
1.00E+02 1.00E+01 2.38E+01
1.00E+03 1.00E+02 9.46E+01
1.00E+05 2.00E+03 1.50E+03
1.00E+06 5.00E+03 5.97E+03
1.00E+07 2.50E+04 2.38E+04
1.00E+08 1.00E+05 9.46E+04

If you want something more natural, reduce the exponent from 0.6 to
0.5 so it becomes the square root.

I have no opinion on the suitability of this, I'm just crunching the
numbers for you.

Cheers,

Jeff