[tarantool-patches] Re: [PATCH 3/9] vinyl: use uncompressed run size for range split/coalesce/compaction

[Konstantin Osipov <kostja@tarantool.org>]

* Vladimir Davydov <vdavydov.dev@gmail.com> [19/01/21 13:15]:
> On Mon, Jan 21, 2019 at 12:17:02AM +0300, Vladimir Davydov wrote:
> > Historically, when considering splitting or coalescing a range or
> > updating compaction priority, we use sizes of compressed runs (see
> > bytes_compressed). This makes the algorithms dependent on whether
> > compression is used or not and how effective it is, which is weird,
> > because compression is a way of storing data on disk - it shouldn't
> > affect the way data is partitioned. E.g. if we turned off compression
> > at the first LSM tree level, which would make sense, because it's
> > relatively small, we would affect the compaction algorithm because
> > of this.
> > 
> > That said, let's use uncompressed run sizes when considering range
> > tree transformations.
> 
> This results in occasional failures of vinyl/deferred_delete.test.lua.
> I amended the patch on the branch to fix this. Here's the diff:
> 

I don't understand why you had to replace random data with
string.rep('z', ...). Otherwise lgtm.

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