Return-Path: X-Original-To: apmail-hbase-issues-archive@www.apache.org Delivered-To: apmail-hbase-issues-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 646F610C9D for ; Wed, 23 Oct 2013 18:50:16 +0000 (UTC) Received: (qmail 37548 invoked by uid 500); 23 Oct 2013 18:49:59 -0000 Delivered-To: apmail-hbase-issues-archive@hbase.apache.org Received: (qmail 37412 invoked by uid 500); 23 Oct 2013 18:49:53 -0000 Mailing-List: contact issues-help@hbase.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Delivered-To: mailing list issues@hbase.apache.org Received: (qmail 37272 invoked by uid 99); 23 Oct 2013 18:49:48 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 23 Oct 2013 18:49:48 +0000 Date: Wed, 23 Oct 2013 18:49:48 +0000 (UTC) From: "stack (JIRA)" To: issues@hbase.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HBASE-9272) A parallel, unordered scanner 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/HBASE-9272?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13803136#comment-13803136 ] stack commented on HBASE-9272: ------------------------------ +1 on v3 On commit add a bit of doc around the 'scaling factor' in javadoc -- you say what it is in the shell but in the methods so its confusing seeing a double returned. Is the test failure yours? Let me rerun the patch. > A parallel, unordered scanner > ----------------------------- > > Key: HBASE-9272 > URL: https://issues.apache.org/jira/browse/HBASE-9272 > Project: HBase > Issue Type: New Feature > Reporter: Lars Hofhansl > Assignee: Lars Hofhansl > Priority: Minor > Fix For: 0.98.0, 0.94.13, 0.96.1 > > Attachments: 9272-0.94.txt, 9272-0.94-v2.txt, 9272-0.94-v3.txt, 9272-0.94-v4.txt, 9272-trunk.txt, 9272-trunk-v2.txt, 9272-trunk-v3.txt, ParallelClientScanner.java, ParallelClientScanner.java > > > The contract of ClientScanner is to return rows in sort order. That limits the order in which region can be scanned. > I propose a simple ParallelScanner that does not have this requirement and queries regions in parallel, return whatever gets returned first. > This is generally useful for scans that filter a lot of data on the server, or in cases where the client can very quickly react to the returned data. > I have a simple prototype (doesn't do error handling right, and might be a bit heavy on the synchronization side - it used a BlockingQueue to hand data between the client using the scanner and the threads doing the scanning, it also could potentially starve some scanners long enugh to time out at the server). > On the plus side, it's only a 130 lines of code. :) -- This message was sent by Atlassian JIRA (v6.1#6144)