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 44D4B17DF7 for ; Wed, 1 Apr 2015 18:38:53 +0000 (UTC) Received: (qmail 40701 invoked by uid 500); 1 Apr 2015 18:38:53 -0000 Delivered-To: apmail-hive-issues-archive@hive.apache.org Received: (qmail 40680 invoked by uid 500); 1 Apr 2015 18:38:53 -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 40669 invoked by uid 99); 1 Apr 2015 18:38:53 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 01 Apr 2015 18:38:53 +0000 Date: Wed, 1 Apr 2015 18:38:53 +0000 (UTC) From: "Sergey Shelukhin (JIRA)" To: issues@hive.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HIVE-10128) BytesBytesMultiHashMap does not allow concurrent read-only access 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-10128?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14391176#comment-14391176 ] Sergey Shelukhin commented on HIVE-10128: ----------------------------------------- [~hagleitn] ping? > BytesBytesMultiHashMap does not allow concurrent read-only access > ----------------------------------------------------------------- > > Key: HIVE-10128 > URL: https://issues.apache.org/jira/browse/HIVE-10128 > Project: Hive > Issue Type: Bug > Reporter: Gopal V > Assignee: Sergey Shelukhin > Fix For: llap > > Attachments: HIVE-10128.01.patch, HIVE-10128.02.patch, HIVE-10128.03.patch, HIVE-10128.patch, hashmap-after.png, hashmap-sync-source.png, hashmap-sync.png > > > The multi-threaded performance takes a serious hit when LLAP shares hashtables between the probe threads running in parallel. > !hashmap-sync.png! > This is an explicit synchronized block inside ReusableRowContainer which triggers this particular pattern. > !hashmap-sync-source.png! > Looking deeper into the code, the synchronization seems to be caused due to the fact that WriteBuffers.setReadPoint modifies the otherwise read-only hashtable. > To generate this sort of result, run LLAP at a WARN log-level, to avoid all the log synchronization that otherwise affects the thread sync. -- This message was sent by Atlassian JIRA (v6.3.4#6332)