From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-2.8 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,FORGED_GMAIL_RCVD, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=no autolearn_force=no version=3.4.2 Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id D61E31F454 for ; Fri, 8 Nov 2019 17:20:56 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:subject:references:to:from:message-id:date :mime-version:in-reply-to:content-type :content-transfer-encoding; q=dns; s=default; b=I/0TD0UHcnBFsz1p ZBkbZk1Hbu6QzVFtOzo3y+fPWbigQFu1uwPh9h6XiM8tQ3PdS8hI0VlPlDGddIFZ YBh7AXU5SrbvgGneHtdLgDlaBGG9E7XKXMUiAvd+l6HDPkZkR+1bpW9I/3pSzrpd giwlJOSmFZjehVPDr09VxqI7Ee8= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:subject:references:to:from:message-id:date :mime-version:in-reply-to:content-type :content-transfer-encoding; s=default; bh=G/vtXHoM6H8zqOpXLx8Q8r MmyhY=; b=m8RjkEhPAUudr53KuNgXiaLAfn+iiNyPK7sa8LFkhm3UAPMSlvrSqb +J3N5/y/vBK/BIk/FymOz8zA8Vw2PCzkDcEgS6DeQYhZkyce19FMLMNoN63vjvrt ck/ZWsRlpwFbnzZXKZeteamgYNeSQYy31hGBjgDViVO7pCst7pL1I= Received: (qmail 98105 invoked by alias); 8 Nov 2019 17:20:54 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 98097 invoked by uid 89); 8 Nov 2019 17:20:54 -0000 Authentication-Results: sourceware.org; auth=none X-HELO: mail-wm1-f50.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:references:to:from:message-id:date:user-agent:mime-version :in-reply-to:content-transfer-encoding:content-language; bh=0yawElLi1bMHCQPMG55SBkr82J42EjgfaoudQXVUBFk=; b=LleaOii0ujJBkAou3grJ4uhFE/NCrHE4YibZLRPeef1SZeqglg96rov16cZV9t2QzY f6cEn3iAIY6UgH1g8ii70vSms9INLfZ9guUJ8JHHRD5/Gi0a2pMYfoVIkFlpcfVNsKsX iplFwlLn1eArxdwhcOUO7mCygUYY2Ij8L3PJVKJdX1iX2El4gAoIphS+DbTs+LZg6IA8 VxyzVmkheUfe/Ok1ScJxdzkJDTHbqfObQaKeSpv3pUX+XC2zim4edZpIPQ5M0jxsaA1o qy7IFe6n8gdwQX2MSrvcjT5ultoGqHqJNZNQVNTUdWQdhvvuKixFZtS6Q633bJiU9XK2 BC0A== Subject: Fwd: Increasing resolver timeout References: To: glibc developers From: Alberto Salvia Novella X-Forwarded-Message-Id: Message-ID: <7c4eba31-5da1-0d9a-7115-1dc00e0c0c04@gmail.com> Date: Fri, 8 Nov 2019 18:20:48 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit For example we have the following bug: $ time ping -c1 "google.com"" 0% packet loss 0m5,064s $ time (ip=$(getent ahostsv4 "google.es" | awk '{ print $1 }' | head -n1); ping -c1 "${ip}") 0% packet loss 0m0,042s The extra time on the first case it's caused by a router mistakenly not returning the IPv6 DNS reply, so the command just sits till it timeouts. The point is this, the bug has been there for a long time unnoticed simply because with 5s timeout the delay simply felt within normal. It wasn't till I started programing server stuff where I noticed that retrieving the data just took so long. So probably we would be better having a longer timeout, like about 10s. So if there is any network anomaly it would be obvious to any person operating it. Alberto