From dev-return-75752-archive-asf-public=cust-asf.ponee.io@zookeeper.apache.org Mon Nov 12 08:11:05 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 A30BB180660 for ; Mon, 12 Nov 2018 08:11:04 +0100 (CET) Received: (qmail 57938 invoked by uid 500); 12 Nov 2018 07:11:03 -0000 Mailing-List: contact dev-help@zookeeper.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@zookeeper.apache.org Delivered-To: mailing list dev@zookeeper.apache.org Received: (qmail 57925 invoked by uid 99); 12 Nov 2018 07:11:03 -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; Mon, 12 Nov 2018 07:11:03 +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 DC424C2299 for ; Mon, 12 Nov 2018 07:11:02 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd4-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: -110.301 X-Spam-Level: X-Spam-Status: No, score=-110.301 tagged_above=-999 required=6.31 tests=[ENV_AND_HDR_SPF_MATCH=-0.5, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, USER_IN_DEF_SPF_WL=-7.5, USER_IN_WHITELIST=-100] 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 A0Kg2RsREK3W for ; Mon, 12 Nov 2018 07:11:01 +0000 (UTC) Received: from mailrelay1-us-west.apache.org (mailrelay1-us-west.apache.org [209.188.14.139]) by mx1-lw-eu.apache.org (ASF Mail Server at mx1-lw-eu.apache.org) with ESMTP id 5585460EBA for ; Mon, 12 Nov 2018 07:11:01 +0000 (UTC) Received: from jira-lw-us.apache.org (unknown [207.244.88.139]) by mailrelay1-us-west.apache.org (ASF Mail Server at mailrelay1-us-west.apache.org) with ESMTP id 9823FE00CB for ; Mon, 12 Nov 2018 07:11:00 +0000 (UTC) Received: from jira-lw-us.apache.org (localhost [127.0.0.1]) by jira-lw-us.apache.org (ASF Mail Server at jira-lw-us.apache.org) with ESMTP id 36FE6266F9 for ; Mon, 12 Nov 2018 07:11:00 +0000 (UTC) Date: Mon, 12 Nov 2018 07:11:00 +0000 (UTC) From: "maoling (JIRA)" To: dev@zookeeper.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (ZOOKEEPER-3186) bug in barrier example code 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/ZOOKEEPER-3186?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16683314#comment-16683314 ] maoling commented on ZOOKEEPER-3186: ------------------------------------ [~pancheng] Pardon me,where can i find your review comments? > bug in barrier example code > --------------------------- > > Key: ZOOKEEPER-3186 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-3186 > Project: ZooKeeper > Issue Type: Bug > Components: documentation > Reporter: cheng pan > Priority: Major > > the code given in the documentation > {code:java} > while (true) { > synchronized (mutex) { > List list = zk.getChildren(root, true); > if (list.size() < size) { > mutex.wait(); > } else { > return true; > } > } > } > {code} > When some nodes are not ready, the code calls mutex.wait() and waits for the watcher event to call mutex.notify() to wake it up. The problem is, we can't guarantee that mutex.notify() will definitely happen after mutex.wait(), which will cause client is stuck. > The solution might be CountDownLatch? -- This message was sent by Atlassian JIRA (v7.6.3#76005)