Return-Path: X-Original-To: archive-asf-public-internal@cust-asf2.ponee.io Delivered-To: archive-asf-public-internal@cust-asf2.ponee.io Received: from cust-asf.ponee.io (cust-asf.ponee.io [163.172.22.183]) by cust-asf2.ponee.io (Postfix) with ESMTP id 2674D200BF3 for ; Wed, 21 Dec 2016 22:38:05 +0100 (CET) Received: by cust-asf.ponee.io (Postfix) id 236D4160B18; Wed, 21 Dec 2016 21:38:05 +0000 (UTC) Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by cust-asf.ponee.io (Postfix) with SMTP id 7549D160B26 for ; Wed, 21 Dec 2016 22:38:04 +0100 (CET) Received: (qmail 97423 invoked by uid 500); 21 Dec 2016 21:37:58 -0000 Mailing-List: contact issues-help@drill.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@drill.apache.org Delivered-To: mailing list issues@drill.apache.org Received: (qmail 97192 invoked by uid 99); 21 Dec 2016 21:37:58 -0000 Received: from arcas.apache.org (HELO arcas) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 21 Dec 2016 21:37:58 +0000 Received: from arcas.apache.org (localhost [127.0.0.1]) by arcas (Postfix) with ESMTP id 723332C0059 for ; Wed, 21 Dec 2016 21:37:58 +0000 (UTC) Date: Wed, 21 Dec 2016 21:37:58 +0000 (UTC) From: "Rahul Challapalli (JIRA)" To: issues@drill.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Created] (DRILL-5148) Replace hash-distribution with a simple round-robin distribution for a simple order by query MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 archived-at: Wed, 21 Dec 2016 21:38:05 -0000 Rahul Challapalli created DRILL-5148: ---------------------------------------- Summary: Replace hash-distribution with a simple round-robin d= istribution for a simple order by query Key: DRILL-5148 URL: https://issues.apache.org/jira/browse/DRILL-5148 Project: Apache Drill Issue Type: Bug Components: Execution - Relational Operators, Query Planning & Op= timization Affects Versions: 1.10.0 Reporter: Rahul Challapalli git.commit.id.abbrev=3Dcf2b7c7 The below plan indicates that we use hash-distribution to avoid data skew. = However in the below case a simple round-robin approach would be sufficient {code} explain plan for select * from dfs.`/drill/testdata/resource-manager/5kwide= columns_500k.tbl` order by columns[0]; +------+------+ | text | json | +------+------+ | 00-00 Screen 00-01 Project(*=3D[$0]) 00-02 Project(T2=C2=A6=C2=A6*=3D[$0]) 00-03 SingleMergeExchange(sort0=3D[1 ASC]) 01-01 SelectionVectorRemover 01-02 Sort(sort0=3D[$1], dir0=3D[ASC]) 01-03 Project(T2=C2=A6=C2=A6*=3D[$0], EXPR$1=3D[$1]) 01-04 HashToRandomExchange(dist0=3D[[$1]]) 02-01 UnorderedMuxExchange 03-01 Project(T2=C2=A6=C2=A6*=3D[$0], EXPR$1=3D[$1], E= _X_P_R_H_A_S_H_F_I_E_L_D=3D[hash32AsDouble($1)]) 03-02 Project(T2=C2=A6=C2=A6*=3D[$0], EXPR$1=3D[ITEM= ($1, 0)]) 03-03 Project(T2=C2=A6=C2=A6*=3D[$0], columns=3D[$= 1]) 03-04 Scan(groupscan=3D[EasyGroupScan [selection= Root=3Dmaprfs:/drill/testdata/resource-manager/5kwidecolumns_500k.tbl, numF= iles=3D1, columns=3D[`*`], files=3D[maprfs:///drill/testdata/resource-manag= er/5kwidecolumns_500k.tbl]]]) {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)