From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-f196.google.com (mail-lj1-f196.google.com [209.85.208.196]) (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 C644F469719 for ; Fri, 20 Mar 2020 16:33:06 +0300 (MSK) Received: by mail-lj1-f196.google.com with SMTP id y17so6369031ljk.12 for ; Fri, 20 Mar 2020 06:33:06 -0700 (PDT) Date: Fri, 20 Mar 2020 16:33:02 +0300 From: Cyrill Gorcunov Message-ID: <20200320133302.GG8326@uranus> References: <20200320081956.30650-1-gorcunov@gmail.com> <20200320081956.30650-12-gorcunov@gmail.com> <20200320102254.GB20273@atlas> <20200320102956.GD8326@uranus> <20200320105842.GA30252@atlas> <20200320111224.GE8326@uranus> <20200320130905.GA29536@atlas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200320130905.GA29536@atlas> Subject: Re: [Tarantool-patches] [PATCH v15 11/11] box/journal: redesign journal operations List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Konstantin Osipov , tml On Fri, Mar 20, 2020 at 04:09:05PM +0300, Konstantin Osipov wrote: > * Cyrill Gorcunov [20/03/20 14:15]: > > On Fri, Mar 20, 2020 at 01:58:42PM +0300, Konstantin Osipov wrote: > > > * Cyrill Gorcunov [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? > > But aren't you using the same callback for sync and async now? Yes, but this is only because we _have_ to use callbacks in wal engine for both sync\async writes. The general architecture is that - sync writes do _not_have_ to use callbacks. The use of callback in wal is transparent to the caller. At least I tried to make it so. > And if you are not using callback for sync, why do you need to > manipulate with txn in sync? > > I'm lost, I accept it. Because of wal and async engine in it :( Look the whole idea is the following: - journal_write_async always use write_async_cb - journal_write should not use async write (or it could but transparently) - journal_write can complete transaction by self, for this sake it tests for TXN_IS_DONE bit and doesn't call for txn_complete if bit is set. You know, I think we're in good shape right now and can cleanup the series on top maybe? > > 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(); > > My point is simple: can we avoid the whole mess of clearing and > restoring fiber txn for sync write calls? Letme think about it. But I would prefer to make it on top.