[tarantool-patches] Re: [PATCH 18/18] vinyl: throttle tx rate if dump does not catch up

[Konstantin Osipov]

* Konstantin Osipov <kostja at tarantool.org> [18/08/23 23:55]:
> * Vladimir Davydov <vdavydov.dev at gmail.com> [18/08/16 23:03]:
> > If the rate at which transactions are ready to write to the database is
> > greater than the dump bandwidth, memory will get depleted before the
> > last dump is complete and all newer transactions will have to wait until
> > the dump has been completed, which may take seconds or even minutes:
> 
> Why are you limiting the rate only during a dump? What about
> compaction throughtput? Write amplification from compaction is
> 10x+ times higher than from dump, compaction is actually the main
> consumer of disk bandwidth. Shouldn't you throttle writes when
> write bandwidth is higher than write amplification/disk bandwidth?


if (disk bandwidth/write amplification > write bandwidth)
    throttle writes;
else
    expedite compaction

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