From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Lars Ingebrigtsen Newsgroups: gmane.emacs.devel Subject: Re: sqlite3 Date: Tue, 28 Dec 2021 15:41:34 +0100 Message-ID: <871r1waj1d.fsf@gnus.org> References: <87tufmjyai.fsf@gnus.org> <831r288vne.fsf@gnu.org> <83zgow7fpi.fsf@gnu.org> <83y24g7dui.fsf@gnu.org> <8735mnr5cb.fsf@gnus.org> <83bl19zwwy.fsf@gnu.org> <87bl18g7r3.fsf@gnus.org> <83ee64ych1.fsf@gnu.org> <83o853pydo.fsf@gnu.org> <875yrbzjc5.fsf@gnus.org> <8335mfpox7.fsf@gnu.org> <83pmpjo79j.fsf@gnu.org> <83ilvbo2ab.fsf@gnu.org> <83h7avo1l6.fsf@gnu.org> <87o852cl7z.fsf@gnus.org> <83r19ym6vv.fsf@gnu.org> <87k0fqaxy8.fsf@gnus.org> <83o852m661.fsf@gnu.org> <83lf06m1ll.fsf@gnu.org> <87v8z99p1s.fsf@gnus.org> <83wnjolw37.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="31357"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) Cc: emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Dec 28 15:42:36 2021 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1n2DgS-0007zr-Mn for ged-emacs-devel@m.gmane-mx.org; Tue, 28 Dec 2021 15:42:36 +0100 Original-Received: from localhost ([::1]:38818 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n2DgR-00050O-A0 for ged-emacs-devel@m.gmane-mx.org; Tue, 28 Dec 2021 09:42:35 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:48576) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n2Dfg-0004Ja-9H for emacs-devel@gnu.org; Tue, 28 Dec 2021 09:41:48 -0500 Original-Received: from [2a01:4f9:2b:f0f::2] (port=41096 helo=quimby.gnus.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n2Dfd-0004Xs-FA; Tue, 28 Dec 2021 09:41:47 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnus.org; s=20200322; h=Content-Type:MIME-Version:Message-ID:In-Reply-To:Date: References:Subject:Cc:To:From:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=5zALjlAtUFLpURbWWh4Si2mVV1J78XT7ECArE5m8tCU=; b=TXUGeD1cKJO/Xywcl50ugJ9cGQ X8sqMHqHewyZvFH9JSiVCk4L4ltu2xJvRMxxSWVeGsNEQ6KMmFBO7UwU/UDkbS9TmiFFlFG0+p1jL shQpqT7afiCiu5LMdev5rbi/Ns7baCAxx1yxJEiOZOYyluY+jdBXY+9SXH9gka8rTPc4=; Original-Received: from [84.212.220.105] (helo=xo) by quimby.gnus.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1n2DfU-0007Kt-Cm; Tue, 28 Dec 2021 15:41:39 +0100 Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwBAMAAAClLOS0AAAABGdBTUEAALGPC/xhBQAAACBj SFJNAAB6JgAAgIQAAPoAAACA6AAAdTAAAOpgAAA6mAAAF3CculE8AAAAGFBMVEX7+vbb1s/Fvret opySg3yKdnFrWlX///+5nBMEAAAAAWJLR0QHFmGI6wAAAAd0SU1FB+UMHA4VHHxIsuYAAAGYSURB VDjLxVNRktsgDJV7AsQJCnTyb4lcoNh7AawcYLP4/keowIQ4mdmZTn/67A9bTxJIegL4r7BoTn8T wmQmY/4x2d8ifEfQcbL3+AajD1ZC4Y73zA6i4cSAP+Nbwp0JemMa6RCCD1zR+Wp33jqnqaj7Wqxv c8e5E+QDUaih/ohmBn5Bu5nVeAf9gKOolsk7bUj/rk7VIa6iyFSp/iOyLXlJI6cDtTAvyypbStyJ eh1YF9niykuOaqi3ClQrI8jqtWlE5muikYkYUpQo+y5SpDAHppg0hn8Di/rue5E1R7kt23oV0YQE mkFupcWnj02NN5F6T0i3/Ql12UiP/pUIhrF8lY+9bInIaRvNkxD55NYZMERaebPloO2znrGJGXCq xF2rclZnYEO+/JwQ46GrWIh6IwNdZjNhVz/f3VMCAcdygJ1733W2niyObTlmbNvUXZ3fg7CzfRVV m50Sl/tDWZ1Q34zZah0PTbkeoEL/MWOt4yXVWJPrPZwJM5b3qc4jYmpBqLoi5rcdMLUuuJbXiLEG I9Pb5vwBnmqG4gFQXfsAAAAldEVYdGRhdGU6Y3JlYXRlADIwMjEtMTItMjhUMTQ6MjE6MjgrMDA6 MDA2miAIAAAAJXRFWHRkYXRlOm1vZGlmeQAyMDIxLTEyLTI4VDE0OjIxOjI4KzAwOjAwR8eYtAAA AABJRU5ErkJggg== X-Now-Playing: Static's _Eject Your Mind_: "Sometimes I'm Sad For A Few Seconds" In-Reply-To: <83wnjolw37.fsf@gnu.org> (Eli Zaretskii's message of "Tue, 28 Dec 2021 15:04:12 +0200") X-Host-Lookup-Failed: Reverse DNS lookup failed for 2a01:4f9:2b:f0f::2 (failed) Received-SPF: pass client-ip=2a01:4f9:2b:f0f::2; envelope-from=larsi@gnus.org; helo=quimby.gnus.org X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:283510 Archived-At: Eli Zaretskii writes: >> Yes, that would explain what we're seeing. Is there any chance the w32 >> stat emulation could be fixed to support sub-second resolutions like it >> does on other systems? > > It could, but it's not a trivial job, and doing it just for this use > case could be overkill. Well, it wouldn't be just for this. Sub-second file resolution is generally useful. >> If not, I think we'll have to change how the values are stored, and add >> a "header" section in the files themselves, so you'd have > > I think this is a good idea anyway. Because we could have fast > machines and disks that defeat even the best time resolution. > >> --- >> Timestamp: > > Do we really need time? That could fail due to clock skew, if the > values are modified from different machines. Wouldn't just a single > "generation number", that keeps only increasing, be enough? That would also be fine -- it's what we're using on the sqlite backend in multisession. But I'm not very enthusiastic about having a synchronised multisession variable access reading and parsing a file each time, so I'm leaning towards just keeping the code as is and adjusting the test on Windows (and other systems that don't have sub-second resolution). Synchronised multisession variables offer no guarantees -- having two Emacsen updating the variable at the same time is inherently racy, and we're doing a best effort kind of thing. So this will be slightly less spiffy on Windows, and that's fine. -- (domestic pets only, the antidote for overdose, milk.) bloggy blog: http://lars.ingebrigtsen.no