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 394B1200BE8 for ; Fri, 9 Dec 2016 01:00:23 +0100 (CET) Received: by cust-asf.ponee.io (Postfix) id 37D86160B27; Fri, 9 Dec 2016 00:00:23 +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 82395160B1F for ; Fri, 9 Dec 2016 01:00:22 +0100 (CET) Received: (qmail 28341 invoked by uid 500); 9 Dec 2016 00:00:21 -0000 Mailing-List: contact dev-help@hawq.incubator.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@hawq.incubator.apache.org Delivered-To: mailing list dev@hawq.incubator.apache.org Received: (qmail 28329 invoked by uid 99); 9 Dec 2016 00:00:21 -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; Fri, 09 Dec 2016 00:00:21 +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 1213CC036F for ; Fri, 9 Dec 2016 00:00:21 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd4-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: -7.018 X-Spam-Level: X-Spam-Status: No, score=-7.018 tagged_above=-999 required=6.31 tests=[KAM_LAZY_DOMAIN_SECURITY=1, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, RP_MATCHES_RCVD=-2.999, URIBL_BLOCKED=0.001] autolearn=disabled Received: from mx1-lw-eu.apache.org ([10.40.0.8]) by localhost (spamd4-us-west.apache.org [10.40.0.11]) (amavisd-new, port 10024) with ESMTP id GrNTaApj_tUU for ; Fri, 9 Dec 2016 00:00:19 +0000 (UTC) Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by mx1-lw-eu.apache.org (ASF Mail Server at mx1-lw-eu.apache.org) with SMTP id 947EB5F3F0 for ; Fri, 9 Dec 2016 00:00:18 +0000 (UTC) Received: (qmail 28216 invoked by uid 99); 9 Dec 2016 00:00:17 -0000 Received: from git1-us-west.apache.org (HELO git1-us-west.apache.org) (140.211.11.23) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 09 Dec 2016 00:00:17 +0000 Received: by git1-us-west.apache.org (ASF Mail Server at git1-us-west.apache.org, from userid 33) id 97F82E108E; Fri, 9 Dec 2016 00:00:17 +0000 (UTC) From: dyozie To: dev@hawq.incubator.apache.org Reply-To: dev@hawq.incubator.apache.org References: In-Reply-To: Subject: [GitHub] incubator-hawq-docs pull request #69: HAWQ-1192 - add discussion of heap and... Content-Type: text/plain Message-Id: <20161209000017.97F82E108E@git1-us-west.apache.org> Date: Fri, 9 Dec 2016 00:00:17 +0000 (UTC) archived-at: Fri, 09 Dec 2016 00:00:23 -0000 Github user dyozie commented on a diff in the pull request: https://github.com/apache/incubator-hawq-docs/pull/69#discussion_r91634985 --- Diff: pxf/TroubleshootingPXF.html.md.erb --- @@ -200,4 +200,107 @@ Examine/collect the log messages from `stdout`. ``` sql gpadmin=# SET client_min_messages=NOTICE -``` \ No newline at end of file +``` + + +## Mitigating PXF Memory Issues + +The Java heap size can be a limiting factor in PXF’s ability to serve many concurrent requests or to run queries against large tables. + +You may run into situations where a query will hang or fail with an Out of Memory exception (OOM). This typically occurs when many threads are reading different data fragments from an external table and insufficient heap space exists to open all fragments at the same time. To avert or remedy this situation, Pivotal recommends either increasing the Java maximum heap size or decreasing the Tomcat maximum number of threads. + --- End diff -- There should be some mention of why to modify one vs the other. Is it simply a question of, if you have enough memory you should increase heap size, and only reduce threads if you're out of memory? --- If your project is set up for it, you can reply to this email and have your reply appear on GitHub as well. If your project does not have this feature enabled and wishes so, or if the feature is enabled but not working, please contact infrastructure at infrastructure@apache.org or file a JIRA ticket with INFRA. ---