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 A6F7A10755 for ; Tue, 5 Aug 2014 06:50:14 +0000 (UTC) Received: (qmail 38329 invoked by uid 500); 5 Aug 2014 06:50:13 -0000 Delivered-To: apmail-hbase-issues-archive@hbase.apache.org Received: (qmail 38286 invoked by uid 500); 5 Aug 2014 06:50:13 -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 38273 invoked by uid 99); 5 Aug 2014 06:50:13 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 05 Aug 2014 06:50:13 +0000 Date: Tue, 5 Aug 2014 06:50:13 +0000 (UTC) From: "Lars Hofhansl (JIRA)" To: issues@hbase.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Updated] (HBASE-11667) Comment ClientScanner logic for NSREs. 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-11667?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Lars Hofhansl updated HBASE-11667: ---------------------------------- Summary: Comment ClientScanner logic for NSREs. (was: Simplify ClientScanner logic for NSREs.) > Comment ClientScanner logic for NSREs. > -------------------------------------- > > Key: HBASE-11667 > URL: https://issues.apache.org/jira/browse/HBASE-11667 > Project: HBase > Issue Type: Improvement > Reporter: Lars Hofhansl > Assignee: Lars Hofhansl > Priority: Minor > Fix For: 0.99.0, 2.0.0, 0.94.23, 0.98.6 > > Attachments: 11667-0.94.txt, 11667-trunk.txt, HBASE-11667-0.98.patch, IntegrationTestBigLinkedListWithRegionMovement.patch > > > We ran into an issue with Phoenix where a RegionObserver coprocessor intercepts a scan and returns an aggregate (in this case a count) with a fake row key. It turns out this does not work when the {{ClientScanner}} encounters NSREs, as it uses the last key it saw to reset the scanner to try again (which in this case would be the fake key). > While this is arguably a rare case and one could also argue that a region observer just shouldn't do this... While looking at {{ClientScanner}}'s code I found this logic not necessary. > A NSRE occurred because we contacted a region server with a key that it no longer hosts. This is the start key, so it is always correct to retry with this same key. That simplifies the ClientScanner logic and also make this sort of coprocessors possible, -- This message was sent by Atlassian JIRA (v6.2#6252)