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 1C65D200B57 for ; Fri, 22 Jul 2016 22:44:22 +0200 (CEST) Received: by cust-asf.ponee.io (Postfix) id 1B293160A5A; Fri, 22 Jul 2016 20:44:22 +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 9242A160A6D for ; Fri, 22 Jul 2016 22:44:21 +0200 (CEST) Received: (qmail 13949 invoked by uid 500); 22 Jul 2016 20:44:20 -0000 Mailing-List: contact issues-help@flink.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@flink.apache.org Delivered-To: mailing list issues@flink.apache.org Received: (qmail 13940 invoked by uid 99); 22 Jul 2016 20:44:20 -0000 Received: from arcas.apache.org (HELO arcas) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 22 Jul 2016 20:44:20 +0000 Received: from arcas.apache.org (localhost [127.0.0.1]) by arcas (Postfix) with ESMTP id 7C8C62C0D5E for ; Fri, 22 Jul 2016 20:44:20 +0000 (UTC) Date: Fri, 22 Jul 2016 20:44:20 +0000 (UTC) From: "Greg Hogan (JIRA)" To: issues@flink.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (FLINK-3480) Add hash-based strategy for ReduceFunction MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 archived-at: Fri, 22 Jul 2016 20:44:22 -0000 [ https://issues.apache.org/jira/browse/FLINK-3480?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15390164#comment-15390164 ] Greg Hogan commented on FLINK-3480: ----------------------------------- Today I bumped into the performance discrepancy where a forwarding ship strategy can hurt performance since we can only do a sorted reduce whereas with a partition hash we can use the new hash-combiner. What would be the spilling strategy for a hash-reducer and would this look much different from using the hash-combiner followed by the sort-reducer? > Add hash-based strategy for ReduceFunction > ------------------------------------------ > > Key: FLINK-3480 > URL: https://issues.apache.org/jira/browse/FLINK-3480 > Project: Flink > Issue Type: Sub-task > Components: Local Runtime > Reporter: Fabian Hueske > > This issue is related to FLINK-3477. > While FLINK-3477 proposes to add hash-based combine strategy for ReduceFunction, this issue aims to add a hash-based strategy for the final aggregation. > This will need again a special hash-table aggregation which allows for in-place updates and append updates. However, it also needs to support spilling to disk in case of too tight memory budgets. -- This message was sent by Atlassian JIRA (v6.3.4#6332)