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 46865172F2 for ; Wed, 9 Sep 2015 12:19:50 +0000 (UTC) Received: (qmail 25413 invoked by uid 500); 9 Sep 2015 12:19:47 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 25373 invoked by uid 500); 9 Sep 2015 12:19:47 -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 25363 invoked by uid 99); 9 Sep 2015 12:19:47 -0000 Received: from Unknown (HELO spamd4-us-west.apache.org) (209.188.14.142) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 09 Sep 2015 12:19:47 +0000 Received: from localhost (localhost [127.0.0.1]) by spamd4-us-west.apache.org (ASF Mail Server at spamd4-us-west.apache.org) with ESMTP id 207C0C0252 for ; Wed, 9 Sep 2015 12:19:47 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd4-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: 3.899 X-Spam-Level: *** X-Spam-Status: No, score=3.899 tagged_above=-999 required=6.31 tests=[DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_REPLY=1, HTML_MESSAGE=3, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=disabled Authentication-Results: spamd4-us-west.apache.org (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com Received: from mx1-eu-west.apache.org ([10.40.0.8]) by localhost (spamd4-us-west.apache.org [10.40.0.11]) (amavisd-new, port 10024) with ESMTP id 2w9sBOLFB3Jc for ; Wed, 9 Sep 2015 12:19:35 +0000 (UTC) Received: from mail-qg0-f44.google.com (mail-qg0-f44.google.com [209.85.192.44]) by mx1-eu-west.apache.org (ASF Mail Server at mx1-eu-west.apache.org) with ESMTPS id 2EAA920FF3 for ; Wed, 9 Sep 2015 12:19:34 +0000 (UTC) Received: by qgez77 with SMTP id z77so5428360qge.1 for ; Wed, 09 Sep 2015 05:19:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=uK5/nOTmNc89CuBu82kfQ1Hpo8oygL6YqhLyoF+9jX0=; b=q/8r1XlDaXe3zQLhy+TRlHT7xYyLp6DcosTu8IqIxL3GrZdLpSegrIOLiHcbnSCjyo TeABmDTzH6qn3zGofDH+Gu8/dBMpP4e/BjI80LlFB53vmaGOxnoa8/gT2WDV+u+iNJau MYAVsd+QHZFlY3Ot3dsf6lu7+b+mAa44527d8jvVF594oKCpOsxmXdNKYc1K36JjUkta LJ+VGagPFJGOL9QDkFF44V5FY91Beh98Q/HrGe9wKTKAbIFKlvtzp70wwpjuY9duR4DD ZUp2L1wC8Qn3FdqgZ84E/O7u8m+o3nmsf9EyYz5WCgKegoel65q2591xWHeePuzIjWXN Cyfw== MIME-Version: 1.0 X-Received: by 10.140.202.204 with SMTP id x195mr44012279qha.7.1441801173290; Wed, 09 Sep 2015 05:19:33 -0700 (PDT) Received: by 10.140.109.100 with HTTP; Wed, 9 Sep 2015 05:19:33 -0700 (PDT) In-Reply-To: References: Date: Wed, 9 Sep 2015 08:19:33 -0400 Message-ID: Subject: Re: Question about consistency From: Eric Plowe To: "user@cassandra.apache.org" Content-Type: multipart/alternative; boundary=001a1140dd0ac558a7051f4f7ef1 --001a1140dd0ac558a7051f4f7ef1 Content-Type: text/plain; charset=UTF-8 Interesting. I'll give it a try and report back my findings. Thank you, Michael. On Wednesday, September 9, 2015, Laing, Michael wrote: > Perhaps a variation on > https://issues.apache.org/jira/browse/CASSANDRA-9753? > > You could try setting speculative retry to 0 to avoid cross-dc reads. > > On Wed, Sep 9, 2015 at 7:55 AM, Eric Plowe > wrote: > >> read_repair_chance: 0 >> dclocal_read_repair_chance: 0.1 >> >> >> On Wednesday, September 9, 2015, Laing, Michael < >> michael.laing@nytimes.com >> > wrote: >> >>> What are your read repair settings? >>> >>> On Tue, Sep 8, 2015 at 9:28 PM, Eric Plowe wrote: >>> >>>> To further expand. We have two data centers, Miami and Dallas. Dallas >>>> is our disaster recovery data center. The cluster has 12 nodes, 6 in Miami >>>> and 6 in Dallas. The servers in Miami only read/write to Miami using data >>>> center aware load balancing policy of the driver. We have the problem when >>>> writing and reading to the Miami cluster with LOCAL_QUORUM. >>>> >>>> Regards, >>>> >>>> Eric >>>> >>>> On Tuesday, September 8, 2015, Eric Plowe wrote: >>>> >>>>> Rob, >>>>> >>>>> All writes/reads are happening from DC1. DC2 is a backup. The web app >>>>> does not handle live requests from DC2. >>>>> >>>>> Regards, >>>>> >>>>> Eric Plowe >>>>> >>>>> On Tuesday, September 8, 2015, Robert Coli >>>>> wrote: >>>>> >>>>>> On Tue, Sep 8, 2015 at 4:40 PM, Eric Plowe >>>>>> wrote: >>>>>> >>>>>>> I'm using Cassandra as a storage mechanism for session state >>>>>>> persistence for an ASP.NET web application. I am seeing issues >>>>>>> where the session state is persisted on one page (setting a value: >>>>>>> Session["key"] = "value" and when it redirects to another (from a post back >>>>>>> event) and check for the existence of the value that was set, it doesn't >>>>>>> exist. >>>>>>> >>>>>>> It's a 12 node cluster with 2 data centers (6 and 6) running 2.1.9. >>>>>>> The key space that the column family lives has a RF of 3 for each >>>>>>> data center. The session state provider is using the the datastax csharp >>>>>>> driver v2.1.6. Writes and reads are at LOCAL_QUORUM. >>>>>>> >>>>>> >>>>>> 1) Write to DC_A with LOCAL_QUORUM >>>>>> 2) Replication to DC_B takes longer than it takes to... >>>>>> 3) Read from DC_B with LOCAL_QUORUM, do not see the write from 1) >>>>>> >>>>>> If you want to be able to read your writes from DC_A in DC_B, you're >>>>>> going to need to use EACH_QUORUM. >>>>>> >>>>>> =Rob >>>>>> >>>>>> >>> > --001a1140dd0ac558a7051f4f7ef1 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Interesting. I'll give it a try and report back my findings.

Thank you, Michael.

On Wednesday, September 9,= 2015, Laing, Michael <mich= ael.laing@nytimes.com> wrote:
Perhaps a variation on=C2=A0https://issues.apache.org/= jira/browse/CASSANDRA-9753?

You could try setting sp= eculative retry to 0 to avoid cross-dc reads.

On Wed, Sep 9, 2015 at 7:55 AM, Eri= c Plowe <eric.plowe@gmail.com<= /a>> wrote:
read_repair_chance:= 0
dclocal_read_repair_chance: 0.1


On Wed= nesday, September 9, 2015, Laing, Michael <= michael.laing@nytimes.com> wrote:
=
What are your read repair settings?

On Tue, Sep 8, 2015 at 9:28 PM, Er= ic Plowe <eric.plowe@gmail.com> wrote= :
To further expand. We have two data cen= ters, Miami and Dallas. Dallas is our disaster recovery data center. The cl= uster has 12 nodes, 6 in Miami and 6 in Dallas. The servers in Miami only r= ead/write to Miami using data center aware load balancing policy of the dri= ver. We have the problem when writing and reading to the Miami cluster with= LOCAL_QUORUM.

Regards,

Eric=C2=A0

On Tuesday, September 8, 2015, Eric Plow= e <eric.plowe@gmail.com> wrote:
Rob,

All writes/reads are happening from DC1. DC2 is= a backup. The web app does not handle live requests from DC2.
Regards,

Eric Plowe
<= div>
On Tuesday, September 8, 2015, Robert Coli <rcoli@eventbrite.= com> wrote:
On Tue, Sep 8, 2015 at 4:4= 0 PM, Eric Plowe <eric.plowe@gmail.com> wrote:
I'm using Cassandra as a st= orage mechanism for session state persistence for an ASP.NET web application. I am seeing issues wher= e the session state is persisted on one page (setting a value: Session[&quo= t;key"] =3D "value"=C2=A0and when it redirects to another (f= rom a post back event) and check for the existence of the value that was se= t, it doesn't exist.

It's a 12 node cluster with= 2 data centers (6 and 6) running 2.1.9. The key space that the column fami= ly lives has a RF of 3 for each data center. The session state= provider is using the the datastax csharp driver v2.1.6. Writes and reads = are at LOCAL_QUORUM.=C2=A0

1) Write t= o DC_A with LOCAL_QUORUM
2) Replication to DC_B takes longer than= it takes to...
3) Read from DC_B with LOCAL_QUORUM, do not see t= he write from 1)

If you want to be able to read yo= ur writes from DC_A in DC_B, you're going to need to use EACH_QUORUM.

=3DRob



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