Return-Path: X-Original-To: archive-asf-public-internal@cust-asf2.ponee.io Delivered-To: archive-asf-public-internal@cust-asf2.ponee.io Received: from cust-asf.ponee.io (cust-asf.ponee.io [163.172.22.183]) by cust-asf2.ponee.io (Postfix) with ESMTP id F2863200D4A for ; Tue, 28 Nov 2017 15:11:34 +0100 (CET) Received: by cust-asf.ponee.io (Postfix) id EF5D5160C07; Tue, 28 Nov 2017 14:11:34 +0000 (UTC) Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by cust-asf.ponee.io (Postfix) with SMTP id 3E70D160C01 for ; Tue, 28 Nov 2017 15:11:34 +0100 (CET) Received: (qmail 19583 invoked by uid 500); 28 Nov 2017 14:11:33 -0000 Mailing-List: contact user-help@impala.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@impala.apache.org Delivered-To: mailing list user@impala.apache.org Received: (qmail 19560 invoked by uid 99); 28 Nov 2017 14:11:33 -0000 Received: from pnap-us-west-generic-nat.apache.org (HELO spamd3-us-west.apache.org) (209.188.14.142) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 28 Nov 2017 14:11:33 +0000 Received: from localhost (localhost [127.0.0.1]) by spamd3-us-west.apache.org (ASF Mail Server at spamd3-us-west.apache.org) with ESMTP id 8201C1806DB for ; Tue, 28 Nov 2017 14:11:32 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd3-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: -0.401 X-Spam-Level: X-Spam-Status: No, score=-0.401 tagged_above=-999 required=6.31 tests=[DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=2, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-2.8, RCVD_IN_SORBS_SPAM=0.5, SPF_PASS=-0.001] autolearn=disabled Authentication-Results: spamd3-us-west.apache.org (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com Received: from mx1-lw-us.apache.org ([10.40.0.8]) by localhost (spamd3-us-west.apache.org [10.40.0.10]) (amavisd-new, port 10024) with ESMTP id V7Q1cbZBCFwz for ; Tue, 28 Nov 2017 14:11:31 +0000 (UTC) Received: from mail-yb0-f172.google.com (mail-yb0-f172.google.com [209.85.213.172]) by mx1-lw-us.apache.org (ASF Mail Server at mx1-lw-us.apache.org) with ESMTPS id CA0855F472 for ; Tue, 28 Nov 2017 14:11:30 +0000 (UTC) Received: by mail-yb0-f172.google.com with SMTP id n185so192652yba.6 for ; Tue, 28 Nov 2017 06:11:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=fBZs2SQPw8isnBPW6KJ+Y0xl8hoiyY16N4+OyqlpWTI=; b=Bz6sIF4wcFwl8elQv2HcUbeiHDas1FPcT0aiZu+X2DGpAtl0N1Tw37A0/kFzvyD3ET ZwzDf5I9NeUnRLFXxG7vExANi+o5Iot3EthDxPJnf20j9rcEyIa8y6OFM2/YtoHlXcqt ABKRHQqg2SbyD7lj1IDFvnezWpNq0oax/SQIJkMreqCseYcmGj4t0ONVtpWzdSMABAmS r62HopFhFzPFEfCS72w4kBrDHrXlDNZ14tOf4Uvf5Ln/QOOv4C0wGB/pwH5HHkfb9f90 DWeVz9HT298uIu5PYTV/bad4/LJV6qpaqQIb31i3pSrtxYPsVo/6Ft7SNXsYer9YTc4u IdBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=fBZs2SQPw8isnBPW6KJ+Y0xl8hoiyY16N4+OyqlpWTI=; b=AAv9NzFj21+O47jVhx7qrE57nN58w5Rb391tlxAMBMjH1A41bdc610PnJNXq7p0BUC 1QUz+gIqk2H9p6NW8soyeB2iu6aHKrBaQEZOzcZYgAke/xDHyri9he5rl+jZAHRqsbYi 3VynS0WjsZJ3ExtWbrSOAUTaJaaEKqd40IloqoJTSShnF0gxYm26YwYcSWeioO4b9saI rCp1EQLpC50kqWdwe+bfwvV3f8c7qDZ1ZrsBYysix/aH6LB21LCZJV+vLeeCDWXclEGb kYLydTc51Vao7Yzeskky1AD114XSVEiIVahUfY3BobpY6QmDoToKTM+d3cTbJChm2clE S14w== X-Gm-Message-State: AJaThX5A/AbzqUEiARjUh+XUKsBb8ezAj0rep4GMcLsGiFLeCiXjhp04 8o2cK1dkaVHDLQqQJLEfbGTLFUuqU3jLD7kKqw4ZzQ== X-Google-Smtp-Source: AGs4zMaFe0kGquSt8ms4Uryw+fhEMywqMEV9Hz7USL7ms6t0tNVf+tGBlXOnkyAwP7JCHX34XA0RjrGhWn2OvQ0Kuo8= X-Received: by 10.37.65.75 with SMTP id o72mr26494660yba.355.1511878290322; Tue, 28 Nov 2017 06:11:30 -0800 (PST) MIME-Version: 1.0 Received: by 10.129.160.137 with HTTP; Tue, 28 Nov 2017 06:11:29 -0800 (PST) From: Jason Heo Date: Tue, 28 Nov 2017 23:11:29 +0900 Message-ID: Subject: Any plans for approximate topN query? To: user@impala.incubator.apache.org Content-Type: multipart/alternative; boundary="001a11c00c8e703abf055f0b98d6" archived-at: Tue, 28 Nov 2017 14:11:35 -0000 --001a11c00c8e703abf055f0b98d6 Content-Type: text/plain; charset="UTF-8" Hi, I'm wondering impala team has any plans for approximate topN for single dimension. My Web analytic system mostly serves top n urls. Such a "GROUP BY url ORDER BY pageview LIMIT n" is slow especially for high-cardinality field. Approximate topN can be used instead of GroupBy for single dimension with extremely lower latency. Elastisearch, Druid, and Clickhouse already provide this feature. It would be great if I can use it on Druid. Thanks. Regards, Jason --001a11c00c8e703abf055f0b98d6 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi,

I'm wondering impala= team has any plans for approximate topN for single dimension.

My Web analy= tic system mostly serves top n urls. Such a "GROUP BY url ORDER BY pag= eview LIMIT n" is slow especially for high-cardinality field. Approxim= ate topN can be used instead of GroupBy for single dimension with extremely= lower latency.

Elastisearch, Druid, and Clickhouse already provide this fe= ature.

It would be great if I can use it on Druid.

Thanks.

Regards,
<= div style=3D"font-size:14px">
Jason<= /div>
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