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 B3AA217C2F for ; Sun, 15 Mar 2015 01:03:12 +0000 (UTC) Received: (qmail 21689 invoked by uid 500); 15 Mar 2015 01:03:12 -0000 Delivered-To: apmail-hbase-issues-archive@hbase.apache.org Received: (qmail 21635 invoked by uid 500); 15 Mar 2015 01:03:12 -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 21623 invoked by uid 99); 15 Mar 2015 01:03:12 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 15 Mar 2015 01:03:12 +0000 Date: Sun, 15 Mar 2015 01:03:12 +0000 (UTC) From: "Andrew Purtell (JIRA)" To: issues@hbase.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HBASE-13109) Make better SEEK vs SKIP decisions during scanning 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-13109?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14362125#comment-14362125 ] Andrew Purtell commented on HBASE-13109: ---------------------------------------- Let's see what Lars says first. I'd like to accommodate Phoenix if we can. > Make better SEEK vs SKIP decisions during scanning > -------------------------------------------------- > > Key: HBASE-13109 > URL: https://issues.apache.org/jira/browse/HBASE-13109 > Project: HBase > Issue Type: Improvement > Reporter: Lars Hofhansl > Assignee: Lars Hofhansl > Fix For: 2.0.0, 1.0.1, 1.1.0, 0.98.12 > > Attachments: 13109-0.98-v4.txt, 13109-trunk-v2.txt, 13109-trunk-v3.txt, 13109-trunk-v4.txt, 13109-trunk-v5.txt, 13109-trunk.txt, nextIndexKVChange_new.patch > > > I'm re-purposing this issue to add a heuristic as to when to SEEK and when to SKIP Cells. This has come up in various issues, and I think I have a way to finally fix this now. HBASE-9778, HBASE-12311, and friends are related. > --- Old description --- > This is a continuation of HBASE-9778. > We've seen a scenario of a very slow scan over a region using a timerange that happens to fall after the ts of any Cell in the region. > Turns out we spend a lot of time seeking. > Tested with a 5 column table, and the scan is 5x faster when the timerange falls before all Cells' ts. > We can use the lookahead hint introduced in HBASE-9778 to do opportunistic SKIPing before we actually seek. -- This message was sent by Atlassian JIRA (v6.3.4#6332)