From commits-return-207726-archive-asf-public=cust-asf.ponee.io@cassandra.apache.org Sat Mar 17 19:22:10 2018 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 7F4AA180652 for ; Sat, 17 Mar 2018 19:22:09 +0100 (CET) Received: (qmail 91163 invoked by uid 500); 17 Mar 2018 18:22:03 -0000 Mailing-List: contact commits-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@cassandra.apache.org Delivered-To: mailing list commits@cassandra.apache.org Received: (qmail 91122 invoked by uid 99); 17 Mar 2018 18:22:03 -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; Sat, 17 Mar 2018 18:22:03 +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 E7CB0180334 for ; Sat, 17 Mar 2018 18:22:02 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd3-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: -109.511 X-Spam-Level: X-Spam-Status: No, score=-109.511 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, T_RP_MATCHES_RCVD=-0.01, 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 (spamd3-us-west.apache.org [10.40.0.10]) (amavisd-new, port 10024) with ESMTP id pEHb7Q_AoEjG for ; Sat, 17 Mar 2018 18:22:01 +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 9BF165F230 for ; Sat, 17 Mar 2018 18:22:01 +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 A4A12E0D4B for ; Sat, 17 Mar 2018 18:22:00 +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 33880214A3 for ; Sat, 17 Mar 2018 18:22:00 +0000 (UTC) Date: Sat, 17 Mar 2018 18:22:00 +0000 (UTC) From: "Jeremiah Jordan (JIRA)" To: commits@cassandra.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Comment Edited] (CASSANDRA-14318) Debug logging can create massive performance issues MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/CASSANDRA-14318?page=3Dcom.atla= ssian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId= =3D16403671#comment-16403671 ]=20 Jeremiah Jordan edited comment on CASSANDRA-14318 at 3/17/18 6:21 PM: ---------------------------------------------------------------------- CASSANDRA-10241 created that debug.log to be a =E2=80=9Cproduction=E2=80=9D= debug log. If there are things being logged at DEBUG which cause performan= ce issues we should disable those or move them to TRACE, not turn off the d= ebug.log. was (Author: jjordan): CASSANDRA-10241 creates that debug.log to be a =E2=80=9Cproduction=E2=80=9D= debug log. If there are things being logged at DEBUG which cause performan= ce issues we should disable those or move them to TRACE, not turn off the d= ebug.log. > Debug logging can create massive performance issues > --------------------------------------------------- > > Key: CASSANDRA-14318 > URL: https://issues.apache.org/jira/browse/CASSANDRA-1431= 8 > Project: Cassandra > Issue Type: Bug > Reporter: Alexander Dejanovski > Priority: Major > Labels: lhf, performance > Fix For: 2.2.x, 3.0.x, 3.11.x, 4.x > > Attachments: debuglogging.png, flame22 nodebug sjk svg.png, flame= 22-nodebug-sjk.svg, flame22-sjk.svg, flame_graph_snapshot.png > > > Debug logging can involve in many cases (especially very low latency ones= ) a very important overhead on the read path in 2.2 as we've seen when upgr= ading clusters from 2.0 to 2.2. > The performance impact was especially noticeable on the client side metri= cs, where p99 could go up to 10 times higher, while ClientRequest metrics r= ecorded by Cassandra didn't show any overhead. > Below shows latencies recorded on the client side with debug logging on f= irst, and then without it : > !debuglogging.png! =C2=A0 > We generated a flame graph before turning off debug logging that shows th= e read call stack is dominated by debug logging :=C2=A0 > !flame_graph_snapshot.png! > I've attached the original flame graph for exploration. > Once disabled, the new flame graph shows that the read call stack gets ex= tremely thin, which is further confirmed by client recorded metrics :=C2=A0 > !flame22 nodebug sjk svg.png! > The query pager code has been reworked since 3.0 and it looks like log.de= bug() calls are gone there, but for 2.2 users and to prevent such issues to= appear with default settings, I really think debug logging should be disab= led by default. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscribe@cassandra.apache.org For additional commands, e-mail: commits-help@cassandra.apache.org