From dev-return-48829-archive-asf-public=cust-asf.ponee.io@couchdb.apache.org Sat Oct 5 22:32:19 2019 Return-Path: X-Original-To: archive-asf-public@cust-asf.ponee.io Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [207.244.88.153]) by mx-eu-01.ponee.io (Postfix) with SMTP id 50EDF180644 for ; Sun, 6 Oct 2019 00:32:19 +0200 (CEST) Received: (qmail 3339 invoked by uid 500); 5 Oct 2019 22:32:18 -0000 Mailing-List: contact dev-help@couchdb.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@couchdb.apache.org Delivered-To: mailing list dev@couchdb.apache.org Received: (qmail 3327 invoked by uid 99); 5 Oct 2019 22:32:18 -0000 Received: from Unknown (HELO mailrelay1-lw-us.apache.org) (10.10.3.42) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 05 Oct 2019 22:32:18 +0000 Received: from auth1-smtp.messagingengine.com (auth1-smtp.messagingengine.com [66.111.4.227]) by mailrelay1-lw-us.apache.org (ASF Mail Server at mailrelay1-lw-us.apache.org) with ESMTPSA id E9C2D6222 for ; Sat, 5 Oct 2019 22:32:17 +0000 (UTC) Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailauth.nyi.internal (Postfix) with ESMTP id 7ABBE21731 for ; Sat, 5 Oct 2019 18:32:17 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute4.internal (MEProxy); Sat, 05 Oct 2019 18:32:17 -0400 X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedufedrheefgddujeehucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefhtgfgggfuffhfvfgjkffosehtqh hmtdhhtdejnecuhfhrohhmpeftohgsvghrthcuufgrmhhuvghlucfpvgifshhonhcuoehr nhgvfihsohhnsegrphgrtghhvgdrohhrgheqnecukfhppedukeehrddvvddvrddviedrvd egvdenucfrrghrrghmpehmrghilhhfrhhomheprhhnvgifshhonhdomhgvshhmthhprghu thhhphgvrhhsohhnrghlihhthidqleefgedvtddvjedvqdduudelgeejtdejjedqrhhnvg ifshhonheppegrphgrtghhvgdrohhrghesfhgrshhtmhgrihhlrdhfmhenucevlhhushht vghrufhiiigvpedt X-ME-Proxy: Received: from [198.18.15.66] (unknown [185.222.26.242]) by mail.messagingengine.com (Postfix) with ESMTPA id D585380061 for ; Sat, 5 Oct 2019 18:32:16 -0400 (EDT) From: Robert Samuel Newson Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Subject: Re: CouchDB and future Date: Sat, 5 Oct 2019 23:32:15 +0100 References: <23525b22-b5c4-61c4-5e0f-da628aa1d2c4@rebhu.com> <75714e71-1daf-aed4-3e72-9c5b1461e08d@rebhu.com> <1f03ccd9-1e79-5594-352c-a698dc2bdb61@rebhu.com> <29bd5e87-ff8a-9aae-515b-8aa479ee778e@rebhu.com> <33085D81-CE2B-4C0E-A456-0DB77EF55FBA@apache.org> <24b570fa-17b4-c96b-c4e6-629e6a4c5143@apache.org> <33c315ab-1e9e-ac9a-a3f9-741f1f5c066d@apache.org> <03A075F7-4FF0-4342-A9B1-0BA720B313EB@apache.org> To: CouchDB Developers In-Reply-To: Message-Id: X-Mailer: Apple Mail (2.3445.104.11) Not even that. :) If you have one node, then your dbs are N=3D1 even if = N is set to 3 in config. the code takes the lower of the n setting and = the number of known nodes (which don't have to be up at the time of db = creation). B. > On 5 Oct 2019, at 21:00, Joan Touzet wrote: >=20 > Agree - couldn't find the reference from earlier, but I believe the > rules should be: >=20 > If you have 1 node, set n=3D1. > If you have 2 nodes, set n=3D2. > If you have 3 or more nodes, set n=3D3. >=20 > Anything else is a special case and isn't recommended. >=20 > -Joan >=20 > On 2019-10-05 15:20, Robert Samuel Newson wrote: >> Pulling this sentence out from much earlier in the thread; >>=20 >> "N should be set to the number of nodes." >>=20 >> That's not true and our docs should not say it today or be changed to = say it in the future. >>=20 >> N is how many copies of a document we'll maintain. If you had a 20 = node cluster, you would not want 20 copies of every document. The = default of 3 copies would be sufficient to prevent accidental loss. >>=20 >> B. >>=20 >>> On 4 Oct 2019, at 23:55, Joan Touzet wrote: >>>=20 >>> Thanks for the follow-up. Thinking of >1 active DB per host makes = this >>> calculation a lot more challenging. >>>=20 >>> Sounds like our recently merged default change of q=3D2 will be = fine. >>>=20 >>> -Joan >>>=20 >>>=20 >>> On 2019-10-04 17:40, ermouth wrote: >>>> This tuned out to be interesting, results vary heavily for = different >>>> platforms. >>>>=20 >>>> I included `perftest.html` into Photon design doc. The utility = gives good >>>> insight how q,n impact doc creation, doc update, validate + update, = and >>>> viewindex create/update =E2=80=93 for a particular CouchDB = instance. >>>>=20 >>>> Common observations: >>>> * q=3D1 is only ok for rare special cases (like DBs with dozen = docs) >>>> * it=E2=80=99s ok to have q=3D=3Dcores or q=3D=3Dcores+1 or even = cores+2: write perf drops >>>> a little, but viewindex update is bit faster >>>> * excessive q (say, more than cores=C3=972) negatively impacts = direct write >>>> perf: having q8 for 2core at least halves write perf for most >>>> commodity/lean platforms and hw cfg. >>>>=20 >>>> ermouth >>>>=20 >>>>=20 >>>> =D1=87=D1=82, 11 =D0=B8=D1=8E=D0=BB. 2019 =D0=B3. =D0=B2 18:17, = Joan Touzet : >>>>=20 >>>>> On 2019-07-11 8:05, ermouth wrote: >>>>>>> to help with the documentation step >>>>>>=20 >>>>>> Probably. Please give me a hint what you need. >>>>>=20 >>>>> What default settings right now are wrong for a system with low = RAM, low >>>>> CPU, and slow disk - such as a RaspberryPi v1, or a $15/mo AWS = server? >>>>>=20 >>>>> -Joan >>>>>=20 >>>>>=20 >>>>=20 >>>=20 >>=20 >=20