From: Vladimir Davydov <vdavydov.dev@gmail.com>
To: kostja@tarantool.org
Cc: tarantool-patches@freelists.org
Subject: Re: [PATCH 2/2] vinyl: optimize mem iterator for frequently updated keys
Date: Thu, 28 Feb 2019 14:09:24 +0300 [thread overview]
Message-ID: <20190228110924.jwe4wtfak2rgx64s@esperanza> (raw)
In-Reply-To: <db5f5a7065b7719781b82156272109756d33f707.1551302815.git.vdavydov.dev@gmail.com>
On Thu, Feb 28, 2019 at 12:37:20AM +0300, Vladimir Davydov wrote:
> If a key is frequently updated, iteration to the next key stored in the
> memory level can take quite a while, because:
>
> - In case of GE/GT iterator, vy_mem_iterator_next_key will have to
> iterate the tree from left to right to skip older key versions.
>
> - In case of LE/LT iterator, vy_mem_iterator_find_lsn will have to
> iterate the tree from right to left to find the newest key version
> visible in the read view.
>
> To avoid that, let's fall back on key lookup if we failed to find an
> appropriate statement after one iteration, because in this case there's
> a good chance that there's more statements for this key. This should be
> fine since a lookup in a memory tree is pretty cheap.
> ---
> https://github.com/tarantool/tarantool/commits/dv/vy-optimize-next-key
>
> src/box/vy_mem.c | 80 ++++++++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 57 insertions(+), 23 deletions(-)
Pushed to 2.1. Will backport to 1.10 once stability test passes.
next prev parent reply other threads:[~2019-02-28 11:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 21:37 [PATCH 1/2] vinyl: refactor vy_mem_iterator_seek Vladimir Davydov
2019-02-27 21:37 ` [PATCH 2/2] vinyl: optimize mem iterator for frequently updated keys Vladimir Davydov
2019-02-28 11:09 ` Vladimir Davydov [this message]
2019-02-28 16:02 ` Vladimir Davydov
2019-02-28 11:09 ` [PATCH 1/2] vinyl: refactor vy_mem_iterator_seek Vladimir Davydov
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