Return-Path: X-Original-To: apmail-hive-issues-archive@minotaur.apache.org Delivered-To: apmail-hive-issues-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 3AB2218723 for ; Mon, 23 Nov 2015 19:33:11 +0000 (UTC) Received: (qmail 37678 invoked by uid 500); 23 Nov 2015 19:33:11 -0000 Delivered-To: apmail-hive-issues-archive@hive.apache.org Received: (qmail 37655 invoked by uid 500); 23 Nov 2015 19:33:11 -0000 Mailing-List: contact issues-help@hive.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@hive.apache.org Delivered-To: mailing list issues@hive.apache.org Received: (qmail 37631 invoked by uid 99); 23 Nov 2015 19:33:11 -0000 Received: from arcas.apache.org (HELO arcas) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 23 Nov 2015 19:33:11 +0000 Received: from arcas.apache.org (localhost [127.0.0.1]) by arcas (Postfix) with ESMTP id F05432C14FB for ; Mon, 23 Nov 2015 19:33:10 +0000 (UTC) Date: Mon, 23 Nov 2015 19:33:10 +0000 (UTC) From: "Sergey Shelukhin (JIRA)" To: issues@hive.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HIVE-12492) MapJoin: 4 million unique integers seems to be a probe plateau MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/HIVE-12492?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15022820#comment-15022820 ] Sergey Shelukhin commented on HIVE-12492: ----------------------------------------- Do you have hashtable log of the metrics? Also, what is the load factor and size? > MapJoin: 4 million unique integers seems to be a probe plateau > -------------------------------------------------------------- > > Key: HIVE-12492 > URL: https://issues.apache.org/jira/browse/HIVE-12492 > Project: Hive > Issue Type: Improvement > Components: Query Planning > Affects Versions: 1.3.0, 1.2.1, 2.0.0 > Reporter: Gopal V > Assignee: Gopal V > Fix For: 2.0.0 > > > After 4 million keys, the map-join implementation seems to suffer from a performance degradation. > The hashtable build & probe time makes this very inefficient, even if the data is very compact (i.e 2 ints). > Falling back onto the shuffle join or bucket map-join is useful after 2^22 items. -- This message was sent by Atlassian JIRA (v6.3.4#6332)