On Wed, Jan 11, 2012 at 9:14 PM, Joseph Blomstedt wrote:
>
> Some thoughts to ponder:
>
> 1. Do you allow multiple clients to write to Riak at the same time?
> With concurrent writers, "atomic" can mean multiple things. Do you
> want linearizability? Do you want one writer to fail?
In our particu
entation, there are cases where this is not guaranteed and a
request may be sent to a fallback node. This leads to the behavior
discussed earlier.
Of course, even if we had perfect PW/PR semantics, Riak still only
gives you a limited form of "read your own writes" consistency. The
labels
On Wed, Jan 11, 2012 at 10:56 AM, Vishal Shah wrote:
> To add to Ian's comment, for me personally, this specific characteristic is
> in fact a very important distinguishing feature of Riak vs other scalable KV
> systems. To me, this is what separates
Yes, but it makes it unusable for anything tha
any key.
> This is how Riak makes its availability guarantees, as well as why "absolute
> consistency" is difficult.
But who makes the decision that a partition needs to migrate and where
a key is at any time during that migration? That isn't independently
decided by e
ere will be N (3 by default) partitions responsible for
> storing the associated value. In effect, there are N primaries for any key.
> This is how Riak makes its availability guarantees, as well as why "absolute
> consistency" is difficult.
>
> --
> Ian Plosker
>
why "absolute consistency"
is difficult.
--
Ian Plosker mailto:i...@basho.com)>
Developer Advocate
Basho Technologies, Inc.
On Tuesday, January 10, 2012 at 10:09 PM, Les Mikesell wrote:
> On Tue, Jan 10, 2012 at 8:52 PM, Justin Sheehy (mailto:jus...@basho.com)> wrote:
>
On Tue, Jan 10, 2012 at 8:52 PM, Justin Sheehy wrote:
>
> On Jan 10, 2012, at 9:42 PM, Les Mikesell wrote:
>
>> How do things like mongo and elasticsearch manage atomic operations
>> while still being redundant?
>
> Most such systems use some variant of primary copy replication, also known as
> m
On Jan 10, 2012, at 9:42 PM, Les Mikesell wrote:
> How do things like mongo and elasticsearch manage atomic operations
> while still being redundant?
Most such systems use some variant of primary copy replication, also known as
master/slave replication.
That approach can provide consistency, b
On Tue, Jan 10, 2012 at 4:51 PM, Jon Meredith wrote:
> Hi list,
>
> After some discussion internally we've agreed that setting PR=R, PW=W=DW and
> PR+PW > N is insufficient to guarantee reading your writes.
How do things like mongo and elasticsearch manage atomic operations
while still being redu
Hi list,
After some discussion internally we've agreed that setting PR=R, PW=W=DW
and PR+PW > N is insufficient to guarantee reading your writes.
In the case where PR=quorum, PW=quorum, say for N=3 that would mean
PR=R=PW=W=DW=2 there is at least one case where you would not be
*guaranteed* to rea
Thomas,
I just replicated your setup (at least for the PR gets) and you can
indeed violate PR/PW when you pause a node on a VM. The reason this
happens is that riak's check for PR/PW simply looks at the ring's
preflist for a partition and checks that the required number of
partitions for that pref
On 2012-01-05 22:52, Tim Robinson wrote:
> On a side note, it looks like we've completely highjacked the
> "Absolute consistency" question initially proposed.
Yes, the answers so far doesn't explain the behaviour I have observed.
If that particular key would happen t
Got it. Thanks for the responses and the patience.
Tim
-Original Message-
From: "Joseph Blomstedt"
Sent: Thursday, January 5, 2012 2:14pm
To: "Tim Robinson"
Cc: "Aphyr" , riak-users@lists.basho.com
Subject: Re: Absolute consistency
Internet went down as
Internet went down as I was writing an email. Looks like everyone
already did a great job answering the availability issues. Although, I
might as well chime in as a Basho engineer.
On a side note, it looks like we've completely highjacked the
"Absolute consistency" question ini
On 01/05/2012 12:53 PM, Tim Robinson wrote:
So with the original thread where with N=3 on 3 nodes. The developer
believed each node was getting a copy. When in fact 2 copies went to
a single node. So yes, there's redundancy and the "shock" value can
go away :) My apologies.
That said, I have no
On Thu, Jan 5, 2012 at 2:53 PM, Tim Robinson wrote:
> So with the original thread where with N=3 on 3 nodes. The developer believed
> each node was getting a copy. When in fact 2 copies went to a single node. So
> yes, there's redundancy and the "shock" value can go away :) My apologies.
>
> Tha
y.
>
>
> -Original Message-
> From: "Aphyr"
> Sent: Thursday, January 5, 2012 1:29pm
> To: "Tim Robinson"
> Cc: "Runar Jordahl" , riak-users@lists.basho.com
> Subject: Re: Absolute consistency
>
> On 01/05/2012 12:12 PM, Tim Robinson wrote
--
From: "Aphyr"
Sent: Thursday, January 5, 2012 1:29pm
To: "Tim Robinson"
Cc: "Runar Jordahl" , riak-users@lists.basho.com
Subject: Re: Absolute consistency
On 01/05/2012 12:12 PM, Tim Robinson wrote:
> Thank you for this info. I'm still somewhat confused.
&g
On 01/05/2012 12:12 PM, Tim Robinson wrote:
Thank you for this info. I'm still somewhat confused.
Why would anyone ever want 2 copies on one physical PC? Correct me if
I am wrong, but part of the sales pitch for Riak is that the cost of
hardware is lessened by distributing your data across a clu
2012 1:01pm
To: "Tim Robinson"
Cc: "Runar Jordahl" , riak-users@lists.basho.com
Subject: Re: Absolute consistency
On 01/05/2012 11:44 AM, Tim Robinson wrote:
> Ouch.
>
> I'm shocked that is not considered a major bug. At minimum that kind of stuff
> should be fro
On 01/05/2012 11:44 AM, Tim Robinson wrote:
Ouch.
I'm shocked that is not considered a major bug. At minimum that kind of stuff
should be front and center in their wiki/docs. Here I am thinking n 2 on a 3
node cluster means I'm covered when in fact I am not. It's the whole reason I
gave Riak
m Robinson"
Cc: "Runar Jordahl" , riak-users@lists.basho.com
Subject: Re: Absolute consistency
shocked? dude. chillax. shocked would be like finding out the pope's gots kids.
or we didn't land on the moon. or did we? there is so much magic abstraction
going on here and ju
n fact I am not. It's the whole reason I
> gave Riak consideration.
>
> Tim
>
> -Original Message-
> From: "Runar Jordahl"
> Sent: Thursday, January 5, 2012 12:13pm
> To: "Thomas Bakketun"
> Cc: riak-users@lists.basho.com
> Subject: Re:
Thursday, January 5, 2012 12:13pm
> To: "Thomas Bakketun"
> Cc: riak-users@lists.basho.com
> Subject: Re: Absolute consistency
>
> As Alexander pointed out, N does not mean "a separate PC". There was a
> thread about this earlier:
>
> http://lists.basho
riginal Message-
From: "Runar Jordahl"
Sent: Thursday, January 5, 2012 12:13pm
To: "Thomas Bakketun"
Cc: riak-users@lists.basho.com
Subject: Re: Absolute consistency
As Alexander pointed out, N does not mean "a separate PC". There was a
thread about this ea
As Alexander pointed out, N does not mean "a separate PC". There was a
thread about this earlier:
http://lists.basho.com/pipermail/riak-users_lists.basho.com/2011-February/003316.html
Kind regards
Runar Jordahl
blog.epigent.com
___
riak-users mailing l
it's
> desirable to have absolute consistency. I though it would be possible to
> implement this on top of Riak with the help of pr and wr parameters of
> fetch and store, but when testing this I sometimes get worrying results.
>
> I have at test setup with Riak nodes in three v
Hello,
Riak is based on eventual consistency concept, but sometimes it's
desirable to have absolute consistency. I though it would be possible to
implement this on top of Riak with the help of pr and wr parameters of
fetch and store, but when testing this I sometimes get worrying results.
I
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