From dev-return-36144-archive-asf-public=cust-asf.ponee.io@ignite.apache.org Tue Jul 3 02:20:23 2018 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 [140.211.11.3]) by mx-eu-01.ponee.io (Postfix) with SMTP id 4E4F2180626 for ; Tue, 3 Jul 2018 02:20:23 +0200 (CEST) Received: (qmail 14493 invoked by uid 500); 3 Jul 2018 00:20:22 -0000 Mailing-List: contact dev-help@ignite.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@ignite.apache.org Delivered-To: mailing list dev@ignite.apache.org Received: (qmail 14478 invoked by uid 99); 3 Jul 2018 00:20:21 -0000 Received: from pnap-us-west-generic-nat.apache.org (HELO spamd4-us-west.apache.org) (209.188.14.142) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 03 Jul 2018 00:20:21 +0000 Received: from localhost (localhost [127.0.0.1]) by spamd4-us-west.apache.org (ASF Mail Server at spamd4-us-west.apache.org) with ESMTP id 2018FC0040 for ; Tue, 3 Jul 2018 00:20:21 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd4-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: 0.442 X-Spam-Level: X-Spam-Status: No, score=0.442 tagged_above=-999 required=6.31 tests=[DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, HTML_MESSAGE=2, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1.697, SPF_PASS=-0.001, T_DKIMWL_WL_MED=-0.01] autolearn=disabled Authentication-Results: spamd4-us-west.apache.org (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com Received: from mx1-lw-us.apache.org ([10.40.0.8]) by localhost (spamd4-us-west.apache.org [10.40.0.11]) (amavisd-new, port 10024) with ESMTP id XJ7dFmtufjem for ; Tue, 3 Jul 2018 00:20:20 +0000 (UTC) Received: from mail-pf0-f196.google.com (mail-pf0-f196.google.com [209.85.192.196]) by mx1-lw-us.apache.org (ASF Mail Server at mx1-lw-us.apache.org) with ESMTPS id AA5945F49F for ; Tue, 3 Jul 2018 00:20:19 +0000 (UTC) Received: by mail-pf0-f196.google.com with SMTP id l123-v6so90297pfl.13 for ; Mon, 02 Jul 2018 17:20:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=kYzsNWPFFucOE1P1GMnIQdSj7mYWLWUrfezgllFEglk=; b=CQy3WUVUIW1KEPIZFqTgVoVkJCDtX2ESGeBXPc9q15SYgRk7TKncO02IOv0wr8mfhN vXaS8K4LYRpFiRxyQggMzja0pKkWMK3e02DRV3Py0S0Dqh9QN2OmLu/g37QETLsXVnhu 92ycO7c+P0Fm6fECvecEh63rqzUI7Zojt/xtxulRQzlIVZdnnjRkQ7F7tyoz1ix6XzsC 8A4dbk39iyHB24ywV9cMY0XawCaX66imOvpOMmiHBuHtA0Os4XU5BKMFizaUu5Vztqv7 lw+ErjZcrrO0Z58RdH/2xd9Q8ac1CsuTKRUYWCKnbeH1KaVYkKJcEtOhUZBaFlzifpNf 5cCw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=kYzsNWPFFucOE1P1GMnIQdSj7mYWLWUrfezgllFEglk=; b=N6rzGwA5DQfKrZGt3JX97xKm+CcxIp+lz7ea2os0srl9oy9DJEgRl8x//d62m6bj8o DVbwI908bToFXwXY4Mr8VH64AxB3KFpu+0+rWIrEfUEcnY8nsZlbir69XxcR80JQG8AA gZx5AlgB50Ic+PsX8z0r4TI+8cq1yIK50ZLpDeD0Che68mbpZ0fhZy3F5CNwW+1LC4fb DtBlTH9abu9fGIcWJQqmrFRbROoSmrqSoypdXOCPIifpyQmMxmSRQ+x0IZO8oX4CneTl +2vdwF7y2CRbxlNGBpxYgoEMZwYIm6HBpLkU5FUB7OC+DECw3bhXvyyYxyYvc6Wn3cUw sJgg== X-Gm-Message-State: APt69E0cqjC+mXMTiM0Rsm5uFk5CWy/UXn98fUm2Buv+yQ3Mqx3x6ydt wLOeVfmYp47/IwLd69LKYaAgX4bH3pOUGRWofI/1Sw== X-Google-Smtp-Source: AAOMgpcmPQLZIl23TMKr86RQMkFKXMPCm4b+S8Sbvi3e6wQHURxVbJNYHaqzwvRBYgDloY+54t995oZOKa11W5Oxgw4= X-Received: by 2002:a62:c819:: with SMTP id z25-v6mr26391412pff.44.1530577218682; Mon, 02 Jul 2018 17:20:18 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a17:90a:1864:0:0:0:0 with HTTP; Mon, 2 Jul 2018 17:20:18 -0700 (PDT) In-Reply-To: References: From: John Wilson Date: Mon, 2 Jul 2018 17:20:18 -0700 Message-ID: Subject: Re: A quick question on cluster topology and partitions? To: dev@ignite.apache.org Content-Type: multipart/alternative; boundary="0000000000006bc1ae05700d4756" --0000000000006bc1ae05700d4756 Content-Type: text/plain; charset="UTF-8" Regarding 1. I'm referring to the documentation here, https://apacheignite.readme.io/docs/topology-validation, which states "*Topology validator is used to verify that cluster topology is valid for further cache operations*." and "*If topology validator is not configured, then the cluster topology is always considered to be valid.*" Thanks, On Mon, Jul 2, 2018 at 4:21 PM, Dmitriy Setrakyan wrote: > On Mon, Jul 2, 2018 at 4:03 PM, John Wilson > wrote: > > > Hi, > > > > > > 1. What exactly is a cluster topology? What makes a cluster topology > > invalid for further cache operations? > > > > Cluster topology is a set of Ignite nodes in the cluster. I do not think a > cluster topology could be invalid on its own. Perhaps you are asking about > a situation when after a certain number of node failures/stops we can be in > a situation where all primary and backup copies become inaccessible. In > that case, the cluster should enter a read-only state for the lost > partitions. > > > > 2. Why do we have the concept of partitions in Ignite? Why don't we > > have a key-to-node mapping rather than a key-to-partition and a > > partition-to-node mapping? > > > > Main reason is because there is a finite number of partitions and there is > an infinite number of keys. Whenever ignite topology changes, Ignite must > rebalance data to the new nodes (or to the existing nodes). In this case, > Ignite needs to know when a certain partition is moved to another node. If > there were no partitions, then it would be impossible to tell when to > finish the rebalancing process. > > D. > --0000000000006bc1ae05700d4756--