From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gorcunov@gmail.com>
Received: from mail-lj1-f194.google.com (mail-lj1-f194.google.com
 [209.85.208.194])
 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
 (No client certificate requested)
 by dev.tarantool.org (Postfix) with ESMTPS id 92789469719
 for <tarantool-patches@dev.tarantool.org>;
 Fri, 20 Mar 2020 14:12:27 +0300 (MSK)
Received: by mail-lj1-f194.google.com with SMTP id q19so5911371ljp.9
 for <tarantool-patches@dev.tarantool.org>;
 Fri, 20 Mar 2020 04:12:27 -0700 (PDT)
Date: Fri, 20 Mar 2020 14:12:24 +0300
From: Cyrill Gorcunov <gorcunov@gmail.com>
Message-ID: <20200320111224.GE8326@uranus>
References: <20200320081956.30650-1-gorcunov@gmail.com>
 <20200320081956.30650-12-gorcunov@gmail.com>
 <20200320102254.GB20273@atlas> <20200320102956.GD8326@uranus>
 <20200320105842.GA30252@atlas>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200320105842.GA30252@atlas>
Subject: Re: [Tarantool-patches] [PATCH v15 11/11] box/journal: redesign
	journal operations
List-Id: Tarantool development patches <tarantool-patches.dev.tarantool.org>
List-Unsubscribe: <https://lists.tarantool.org/mailman/options/tarantool-patches>, 
 <mailto:tarantool-patches-request@dev.tarantool.org?subject=unsubscribe>
List-Archive: <https://lists.tarantool.org/pipermail/tarantool-patches/>
List-Post: <mailto:tarantool-patches@dev.tarantool.org>
List-Help: <mailto:tarantool-patches-request@dev.tarantool.org?subject=help>
List-Subscribe: <https://lists.tarantool.org/mailman/listinfo/tarantool-patches>, 
 <mailto:tarantool-patches-request@dev.tarantool.org?subject=subscribe>
To: Konstantin Osipov <kostja.osipov@gmail.com>, tml <tarantool-patches@dev.tarantool.org>

On Fri, Mar 20, 2020 at 01:58:42PM +0300, Konstantin Osipov wrote:
> * Cyrill Gorcunov <gorcunov@gmail.com> [20/03/20 13:34]:
> > > >  
> > > > -	if (txn_write_to_wal(req) != 0)
> > > > +	fiber_set_txn(fiber(), NULL);
> > > > +	if (journal_write(req) != 0) {
> > > > +		fiber_set_txn(fiber(), txn);
> > > 
> > > I wonder why do you need to clear/set txn in txn_commit()?
> 
> Forgive me for being really painful about it, but why not use
> different complete callbacks for sync and async wal writes?-)
> Under the hood they will still call txn_complete(), but one will
> assert, and another will not?

Hmm. If I remember correctly we've been planning to use callbacks
only for async writes. Actually I can introduce callback helper
for sync writes as well but this ruines the whole idea, no?

I can easily hide this bit test inside txn_complete itself and
for sync write there will be plain txn_complete call, like

txn_commit
	...
	journal_write();
	...
	txn_complete();

ie the whole idea was to not use callbacks for sync write, no?
...
> > > >  
> > > > -	/*
> > > > -	 * In case of non-yielding journal the transaction could already
> > > > -	 * be done and there is nothing to wait in such cases.
> > > > -	 */
> > > >  	if (!txn_has_flag(txn, TXN_IS_DONE)) {
> > > > -		bool cancellable = fiber_set_cancellable(false);
> > > > -		fiber_yield();
> > > > -		fiber_set_cancellable(cancellable);
> > > > +		txn->signature = req->res;
> > > > +		txn_complete(txn);
> > > > +		fiber_set_txn(fiber(), NULL);
> > > 
> 
> I mean fiber_set_txn() is done twice, if I am not mistaken.

True, this one is redundant. Thanks!