Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bf99C-0002iM-VM for pgsql-admin@arkaria.postgresql.org; Wed, 31 Aug 2016 17:17:59 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1bf99B-0005ZL-VS for pgsql-admin@arkaria.postgresql.org; Wed, 31 Aug 2016 17:17:58 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1bf97V-0003hR-EG for pgsql-admin@postgresql.org; Wed, 31 Aug 2016 17:16:13 +0000 Received: from www.ipv6.roaringpenguin.com ([2607:f748:1200:fb:70:38:112:54] helo=colo3.roaringpenguin.com) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1bf97R-0002Dz-PI for pgsql-admin@postgresql.org; Wed, 31 Aug 2016 17:16:12 +0000 Received: from vanadium.roaringpenguin.com ([192.168.10.23]) by colo3.roaringpenguin.com (8.14.4/8.14.4/Debian-8) with ESMTP id u7VHG7xQ006109 for ; Wed, 31 Aug 2016 13:16:07 -0400 Received: from hydrogen.roaringpenguin.com (dfs@hydrogen.roaringpenguin.com [192.168.10.1]) by vanadium.roaringpenguin.com (8.14.4/8.14.4/Debian-8) with ESMTP id u7VHG4Ok011921 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 31 Aug 2016 13:16:04 -0400 Date: Wed, 31 Aug 2016 13:16:04 -0400 From: Dianne Skoll To: pgsql-admin Subject: Re: What causes streaming replication delay? Message-ID: <20160831131604.0f305404@hydrogen.roaringpenguin.com> In-Reply-To: References: <20160831114417.7fc1040d@hydrogen.roaringpenguin.com> Organization: Roaring Penguin Software Inc. X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: CanIt (www . roaringpenguin . com) X-Scanned-By: MIMEDefang 2.78 on 192.168.10.23 X-Spam-Score: undef - relay 192.168.10.23 marked with skip_spam_scan X-CanIt-Geo: No geolocation information available for 192.168.10.23 X-CanItPRO-Stream: outgoing (inherits from default) X-CanIt-Archive-Cluster: SQVyZJxqklY5buiWXYCN4T/BjiM X-CanIt-Archived-As: base/20160831 / 01RBRg7k8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=roaringpenguin.com; h= date:from:to:subject:message-id:in-reply-to:references :mime-version:content-type:content-transfer-encoding; s=canit; bh=EK6wSXjCEo1mtDAGl2kWw4xF49+HHNt9FeJ4+8ClBUY=; b=idXMtvqlau14 JU4iOF8Qz4DRJsnEfmXVHj3I0hgMiBuOfe57Ie7bnEi9m8pGL4XtcawNMBH/9cuG KWy0AnZfQxoB07pnJgRJbK2/PCNpy+/HlLB3uxnuE2A0XCxMNMInFri38GG+payZ dShEcUc+FAEd23RbeotCNuh/+eHLtq1NL7uCEQMozE+Zolu9zAJOCigOptqDp4eh UWaCYVLKqKgMEm39UTpwefltRE6OTaH7oAth0qDe18fq0cwX+U4Zn1TuHnAg95Vp oAQBWScldyUi0UHIJ2ffOWzA5hTBtf0jmmF192BRqcZcKnZwPjbe430K1I1OiND/ 0sHegLAw4Q== X-Pg-Spam-Score: -8.5 (--------) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-admin Precedence: bulk Sender: pgsql-admin-owner@postgresql.org On Wed, 31 Aug 2016 12:04:23 -0400 Keith wrote: > All depends on how you're monitoring your slave lag. Check this blog > post and if you're seeing actual byte lag, then you could have cause > for concern. It's not because the master is idle... there is tons of write traffic. And the way I measure the lag is about as directly as you can: I periodically insert a timestamp into a specific table on the master, and then poll the hot-standby until the inserted timestamp has appeared. Regards, Dianne. -- Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin