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Date: Sat, 11 Jul 2020 00:36:01 +0300
From: Cyrill Gorcunov <gorcunov@gmail.com>
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Subject: Re: [Tarantool-patches] [PATCH 3/5] qsync: txn_commit_async -- drop
 redundant variable
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To: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Cc: tml <tarantool-patches@dev.tarantool.org>

On Fri, Jul 10, 2020 at 11:28:26PM +0200, Vladislav Shpilevoy wrote:
> On 10/07/2020 23:10, Cyrill Gorcunov wrote:
> > On Fri, Jul 10, 2020 at 10:35:50PM +0200, Vladislav Shpilevoy wrote:
> >> Опять же. Патч технически корректен, но так же и бесполезен.
> >> Его полезность сравнима с исправлением опечатки в каком-нибудь
> >> не особо нужном комменте. Сори, если токсично звучит.
> >>
> >> Но не вижу в этом патче нужды.
> > 
> > We've to allocate a variable which we simply don't need. Look,
> > the former code reads the flag, puts it into variable then
> > immediately read it and that's all :/ I think we should not
> > spread @is_sync but read the flag as much as possible for
> > better grep'ability.
> 
> Do you have a proof that this change improves anything? That
> the variable 'allocation' on the stack actually happens, and
> costs even 1 ns?

You simply don't need it. I think the compiler will rip it off.
Again, if you suspect that the code gonna be changed then ignoring
the commit is perfectly fine. If not -- the useless variable is just
a bad taste at minimum.