Hi
Using Cassandra 2.0.0.
3 node cluster
Replication 2.
Using consistency ALL for both read and writes.
I have a single thread that reads a value, updates it and writes it back to
the table. The column type is big int. Updating counts for a timestamp.
With single thread and consistency ALL , I
@cassandra.apache.org
Date: Friday, January 10, 2014 at 2:50 PM
To: user@cassandra.apache.org
Subject: Read/Write consistency issue
Hi
Using Cassandra 2.0.0.
3 node cluster
Replication 2.
Using consistency ALL for both read and writes.
I have a single thread that reads a value, updates it and writes
That, or roll your own locking. Means multiple updates, but it works reliably.
tc
From: Robert Wille [mailto:rwi...@fold3.com]
Sent: Friday, January 10, 2014 4:25 PM
To: user@cassandra.apache.org
Subject: Re: Read/Write consistency issue
Cassandra is a last-write wins kind of a deal. The last
...@match.com
Reply-To: user@cassandra.apache.org
Date: Friday, January 10, 2014 at 3:28 PM
To: user@cassandra.apache.org user@cassandra.apache.org
Subject: RE: Read/Write consistency issue
That, or roll your own locking. Means multiple updates, but it works
reliably.
tc
From: Robert Wille
Is it possible to pin to a node, instead of letting the client find the next
node (round robin)?
Sorry, a C* noob here...
tc
From: Robert Wille [mailto:rwi...@fold3.com]
Sent: Friday, January 10, 2014 4:35 PM
To: user@cassandra.apache.org
Subject: Re: Read/Write consistency issue
Actually
.
Robert
From: Todd Carrico todd.carr...@match.com
Reply-To: user@cassandra.apache.org
Date: Friday, January 10, 2014 at 3:28 PM
To: user@cassandra.apache.org user@cassandra.apache.org
Subject: RE: Read/Write consistency issue
That, or roll your own locking. Means multiple updates
From: Todd Carrico todd.carr...@match.com
Reply-To: user@cassandra.apache.org
Date: Friday, January 10, 2014 at 3:28 PM
To: user@cassandra.apache.org user@cassandra.apache.org
Subject: RE: Read/Write consistency issue
That, or roll your own locking. Means multiple updates, but it works
reliably
rapid repeated writing is not an issue. Why would this be bad?
Robert
From: Steven A Robenalt srobe...@stanford.edu
Reply-To: user@cassandra.apache.org
Date: Friday, January 10, 2014 at 3:41 PM
To: user@cassandra.apache.org
Subject: Re: Read/Write consistency issue
My understanding
: Steven A Robenalt srobe...@stanford.edu
Reply-To: user@cassandra.apache.org
Date: Friday, January 10, 2014 at 3:41 PM
To: user@cassandra.apache.org
Subject: Re: Read/Write consistency issue
My understanding is that it's generally a Cassandra anti-pattern to do
read-before-write in any case
, January 10, 2014 4:52 PM
To: user@cassandra.apache.org
Subject: Re: Read/Write consistency issue
Interested in knowing more on why read-before-write is an anti-pattern. In the
next month or so, I intend to use Cassandra as a doc store. One very common
operation will be to read the document, make
]
Sent: Friday, January 10, 2014 5:13 PM
To: user@cassandra.apache.org
Subject: Re: Read/Write consistency issue
It is bad because of the risk of concurrent modifications. If you don't have
some kind of global lock on the document/row, then 2 readers might read version
A, reader 1 writes version
To: user@cassandra.apache.org user@cassandra.apache.org
Subject: RE: Read/Write consistency issue
That, or roll your own locking. Means multiple updates, but it works
reliably.
tc
*From:* Robert Wille [mailto:rwi...@fold3.com rwi...@fold3.com]
*Sent:* Friday, January 10, 2014 4:25 PM
*Subject:* Re: Read/Write consistency issue
It is bad because of the risk of concurrent modifications. If you don't
have some kind of global lock on the document/row, then 2 readers might
read version A, reader 1 writes version B based on A, and reader 2 writes
version C based
this pattern work.
Robert
From: Todd Carrico todd.carr...@match.com
Reply-To: user@cassandra.apache.org
Date: Friday, January 10, 2014 at 3:28 PM
To: user@cassandra.apache.org user@cassandra.apache.org
Subject: RE: Read/Write consistency issue
That, or roll your own locking. Means multiple
work.
Robert
From: Todd Carrico todd.carr...@match.com
Reply-To: user@cassandra.apache.org
Date: Friday, January 10, 2014 at 3:28 PM
To: user@cassandra.apache.org user@cassandra.apache.org
Subject: RE: Read/Write consistency issue
That, or roll your own locking. Means multiple updates
For single thread, consistency ALL it should work. I believe you do
something different. What are these three numbers exactly?
old=60616 val =19 new =60635
On Fri, Jan 10, 2014 at 1:50 PM, Manoj Khangaonkar khangaon...@gmail.comwrote:
Hi
Using Cassandra 2.0.0.
3 node cluster
Replication 2.
old is the value that was read from the column.
val is the value that needs to be added to it.
new is (old + val) that is written back to the column.
regards
On Fri, Jan 10, 2014 at 4:36 PM, Andrey Ilinykh ailin...@gmail.com wrote:
For single thread, consistency ALL it should work. I believe
@cassandra.apache.org
Date: Friday, January 10, 2014 at 4:59 PM
To: user@cassandra.apache.org
Subject: Re: Read/Write consistency issue
As was pointed out earlier, Consistency.ALL is still subject to the
possibility of clock drift between nodes, and there is also the problem of
using the exact same
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