Return-Path: X-Original-To: apmail-cassandra-user-archive@www.apache.org Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 2CD0CDB26 for ; Tue, 2 Oct 2012 12:41:23 +0000 (UTC) Received: (qmail 69287 invoked by uid 500); 2 Oct 2012 12:41:20 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 69141 invoked by uid 500); 2 Oct 2012 12:41:20 -0000 Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@cassandra.apache.org Delivered-To: mailing list user@cassandra.apache.org Received: (qmail 69118 invoked by uid 99); 2 Oct 2012 12:41:20 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 02 Oct 2012 12:41:20 +0000 X-ASF-Spam-Status: No, hits=-2.3 required=5.0 tests=RCVD_IN_DNSWL_MED,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: local policy) Received: from [192.174.58.133] (HELO XEDGEB.nrel.gov) (192.174.58.133) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 02 Oct 2012 12:41:14 +0000 Received: from XHUBB.nrel.gov (10.20.4.59) by XEDGEB.nrel.gov (192.174.58.133) with Microsoft SMTP Server (TLS) id 8.3.245.1; Tue, 2 Oct 2012 06:40:50 -0600 Received: from MAILBOX2.nrel.gov ([fe80::19a0:6c19:6421:12f]) by XHUBB.nrel.gov ([::1]) with mapi; Tue, 2 Oct 2012 06:40:52 -0600 From: "Hiller, Dean" To: "user@cassandra.apache.org" Date: Tue, 2 Oct 2012 06:41:09 -0600 Subject: Re: Read latency issue Thread-Topic: Read latency issue Thread-Index: Ac2gmyg4WbsWkFpZRfW3FqmsPaNzhg== Message-ID: In-Reply-To: <17C39FE466076C46B6E83F129C7B19CE16B6D515@HKXPRD0310MB352.apcprd03.prod.outlook.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Microsoft-MacOutlook/14.2.3.120616 acceptlanguage: en-US Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Interesting results. With PlayOrm, we did a 6 node test of reading 100 row= s from 1,000,000 using PlayOrm Scalable SQL. It only took 60ms. Maybe we = have better hardware though??? We are using 7200 RPM drives so nothing fan= cy on the disk side of things. More nodes puts at a higher throughput thou= gh as reading from more disks will be faster. Anyways, you may want to pla= y with more nodes and re-run. If you run a test with PlayOrm, I would love= to know the results there as well. Later, Dean From: Arindam Barua > Reply-To: "user@cassandra.apache.org" > Date: Monday, October 1, 2012 4:57 PM To: "user@cassandra.apache.org" > Subject: Read latency issue unning a query to like =93select * from where atag=3D=94,= where =91atag=92 is the first column of the composite key, from either JDB= C or Hector (equivalent code), results in read times of 200-300ms from a re= mote host on the same network. The query returned around 800 results. Runni= ng the same query on a Cassandra host results in a read time of ~110-130 ms= . Using read consistency of ONE reduces the read latency by ~20ms, compared t= o using QUORUM. Enabling row cache did not seem to change the performance much. Moreover, t= he row cache =91size=92 according to nodetool was very tiny. Here is a snap= shot of the nodetool info after running few read tests: Key Cache : size 2448 (bytes), capacity 104857584 (bytes), 231 hits,= 266 requests, 1.000 recent hit rate, 14400 save period in seconds Row Cache : size 96 (bytes), capacity 4194304000 (bytes), 9 hits, 13= requests, NaN recent hit rate, 0 save period in seconds