From issues-return-4437-archive-asf-public=cust-asf.ponee.io@phoenix.apache.org Tue Feb 5 00:53:04 2019 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 579EC180651 for ; Tue, 5 Feb 2019 01:53:04 +0100 (CET) Received: (qmail 58994 invoked by uid 500); 5 Feb 2019 00:53:03 -0000 Mailing-List: contact issues-help@phoenix.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@phoenix.apache.org Delivered-To: mailing list issues@phoenix.apache.org Received: (qmail 58985 invoked by uid 99); 5 Feb 2019 00:53:03 -0000 Received: from pnap-us-west-generic-nat.apache.org (HELO spamd1-us-west.apache.org) (209.188.14.142) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 05 Feb 2019 00:53:03 +0000 Received: from localhost (localhost [127.0.0.1]) by spamd1-us-west.apache.org (ASF Mail Server at spamd1-us-west.apache.org) with ESMTP id AAACFCBD4E for ; Tue, 5 Feb 2019 00:53:02 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd1-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: -109.501 X-Spam-Level: X-Spam-Status: No, score=-109.501 tagged_above=-999 required=6.31 tests=[ENV_AND_HDR_SPF_MATCH=-0.5, KAM_ASCII_DIVIDERS=0.8, 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-us.apache.org ([10.40.0.8]) by localhost (spamd1-us-west.apache.org [10.40.0.7]) (amavisd-new, port 10024) with ESMTP id r15i_Hf4SdkT for ; Tue, 5 Feb 2019 00:53:01 +0000 (UTC) Received: from mailrelay1-us-west.apache.org (mailrelay1-us-west.apache.org [209.188.14.139]) by mx1-lw-us.apache.org (ASF Mail Server at mx1-lw-us.apache.org) with ESMTP id 803EE61081 for ; Tue, 5 Feb 2019 00:53:01 +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 F14DFE2673 for ; Tue, 5 Feb 2019 00:53:00 +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 94D5C243FA for ; Tue, 5 Feb 2019 00:53:00 +0000 (UTC) Date: Tue, 5 Feb 2019 00:53:00 +0000 (UTC) From: "Andrew Purtell (JIRA)" To: issues@phoenix.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (PHOENIX-5123) Avoid using MappedByteBuffers for server side GROUP BY 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/PHOENIX-5123?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16760361#comment-16760361 ] Andrew Purtell commented on PHOENIX-5123: ----------------------------------------- RAF just uses a file descriptor, there's no mapping, unless you ask for it. You set a position and then read or write. {quote} Instances of this class support both reading and writing to a random access file. A random access file behaves like a large array of bytes stored in the file system. There is a kind of cursor, or index into the implied array, called the _file pointer_; input operations read bytes starting at the file pointer and advance the file pointer past the bytes read. If the random access file is created in read/write mode, then output operations are also available; output operations write bytes starting at the file pointer and advance the file pointer past the bytes written. Output operations that write past the current end of the implied array cause the array to be extended. The file pointer can be read by the {{getFilePointer}} method and set by the {{seek}} method. {quote} Presumably Phoenix is tracking position so can move or advance the pointer to known locations, and from there you use DataInput or DataOutput methods to write or extract records. > Avoid using MappedByteBuffers for server side GROUP BY > ------------------------------------------------------ > > Key: PHOENIX-5123 > URL: https://issues.apache.org/jira/browse/PHOENIX-5123 > Project: Phoenix > Issue Type: Bug > Reporter: Lars Hofhansl > Priority: Major > > Like PHOENIX-5120 but for GROUP BY. > Solution is a bit more tricky, since outline for sorting the access here is truly random. > [~apurtell] suggests to perhaps just use a RandomAccessFile for this. > (I'm not sure that uses under the hood, though) -- This message was sent by Atlassian JIRA (v7.6.3#76005)