[tarantool-patches] Re: [PATCH 7/9] vinyl: randomize range compaction to avoid IO load spikes

[Konstantin Osipov]

* Vladimir Davydov <vdavydov.dev at gmail.com> [19/02/06 13:57]:
> On Wed, Feb 06, 2019 at 01:44:19PM +0300, Konstantin Osipov wrote:
> > * Vladimir Davydov <vdavydov.dev at gmail.com> [19/02/06 13:31]:
> > > Over how many dumps? What do we do after restart, when there's no
> > > history and perhaps even no level 1?
> > 
> > A am thinking about something along these lines: 
> > f(n+1) = (f(n) + x*k)(1+k) - where k is the weight used to scale
> > the next input
> 
> What should be k equal to?

I don't know.

> Also, what we should do after restart when there's no history?

Seed the function with the top run size. If there is no top run,
seed with 0.
> 
> Why is using the last level size as reference bad?

Because you don't know if it's last or not?

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Konstantin Osipov, Moscow, Russia, +7 903 626 22 32
http://tarantool.io - www.twitter.com/kostja_osipov