http://wiki.apache.org/cassandra/FAQ#range_ghosts
On Sun, Apr 11, 2010 at 5:12 PM, Kevin Wiggen wrote:
>
> I have spent the last few days playing with Cassandra and I have attempted
> to create a simple "Java->Thrift->Cassandra" Discussion Group Server
> (because the world needs another one) to t
On Sat, 2010-04-10 at 10:49 +1200, Todd Nine wrote:
> I want the data that is written from the different partitioned
> processing nodes (our c# app servers) to be available in both data
> centres. I'm assuming I would need an equal number of nodes at each
> data centre, then use the RackAwareStrat
On Fri, 2010-04-09 at 11:28 -0500, Jonathan Ellis wrote:
> The jit on debian may take longer to warm up by default.
Also, the Debian package will pull in OpenJDK by default, but there is
nothing to stop you from using the Sun JVM (which I assume is what's in
use on the other machines). It is even
I have spent the last few days playing with Cassandra and I have attempted to
create a simple "Java->Thrift->Cassandra" Discussion Group Server (because the
world needs another one) to teach myself the data model and try everything out.
With all the great blog posts on cassandra out there, I am
I don't know whether I'm wrong or not (I'm also new to Cassandra). But looks
like we only can query a single Super Column at a single query since these
values are specified in the ColumnParent parameter. Which means that you
only can query a single week or month (as your super column).
From: Ph
Hello,
I would like to know if the following is indeed possible with Cassandra,
from my understanding of key & column slices it is but I am just beggining
to get my head around Cassandra...
I have data that is two dimensional, time varying (think of a grid). At each
cell of this grid,I store a b
On Sun, Apr 11, 2010 at 3:30 AM, Mark Robson wrote:
> Can we not implement counts by just storing all the deltas in a row, and
> then summing them all up to acheive a count.
>
> If a row ends up with too many deltas, a reader could just summarise the
> deltas occasionally into a single value (in a
On Sun, Apr 11, 2010 at 12:10 PM, vineet daniel wrote:
> I assume that using the key i can get the all the columns like an array. Now
> i'd be using php to extract arraykey=>value in that array, just want to
> avoid that i.e i can directly print the column names.
It doesn't work this way. It's
I am dropping the idea, dont want to irritate you guys more. I've got your
points.
On Mon, Apr 12, 2010 at 12:41 AM, Benjamin Black wrote:
> Just to be clear: do you understand we are saying you need to use
> multiple CFs to achieve the goal, not a single one?
>
> The Users CF would be indexed o
Just to be clear: do you understand we are saying you need to use
multiple CFs to achieve the goal, not a single one?
The Users CF would be indexed on a unique integer as you are saying
you intend. There is no point in having values as column names here,
other than making things incredibly confus
I assume that using the key i can get the all the columns like an array. Now
i'd be using php to extract arraykey=>value in that array, just want to
avoid that i.e i can directly print the column names. If you guys think its
not a good idea I can drop it, anyways m new to it and a lot of things ar
I have no idea what problem you are trying to solve. You are
misunderstanding a number of things about the Cassandra data model and
about how we are explaining it is best used.
On Sun, Apr 11, 2010 at 11:37 AM, vineet daniel wrote:
> Well my initial idea is to use value as column name, keeping
Why do you want to directly read column names as values, and what will
you put in the column values?
On Sun, Apr 11, 2010 at 11:37 AM, vineet daniel wrote:
> Well my initial idea is to use value as column name, keeping key as an
> incremental integer. The discussion after each mail has drifted f
Well my initial idea is to use value as column name, keeping key as an
incremental integer. The discussion after each mail has drifted from this
point which I had made. Will put it again.
we want to store user information. We keep 1,2,3,4.so on as keys. AND
values as column names i.e rather t
Row keys must be unique. If your usernames are not unique and you
want to be able to query on them, you either need to figure out a way
to make them unique or treat the username rows themselves as indices,
which refer to a set of actually unique identifiers for users.
On Sun, Apr 11, 2010 at 11:1
Benjamin is pointing out that you must be using the word "username" to
mean something different than he is using it.
BY DEFINITION usernames are unique in the most common use of the word.
So what do you really mean if not "username"?
On Sun, Apr 11, 2010 at 11:12 AM, vineet daniel wrote:
> its n
its not a problem its a scenario, which we need to handle. And all I am
trying to do is to achieve what is not there with API i.e a workaroud.
On Sun, Apr 11, 2010 at 11:06 PM, Benjamin Black wrote:
> A system that permits multiple people to have the same username has a
> serious problem.
>
> On
A system that permits multiple people to have the same username has a
serious problem.
On Sun, Apr 11, 2010 at 6:12 AM, vineet daniel wrote:
> How to handle same usernames. Otherwise seems fine to me.
>
> On Sun, Apr 11, 2010 at 6:17 PM, Dop Sun wrote:
>>
>> Hi,
>>
>>
>>
>> As far as I can see i
Ah, I see what you are doing. No, that won't work. The mistake you
are making is in thinking a CF is a table and that Cassandra is
storing columns. A CF is a namespace and Cassandra stores key/value
pairs, where the keys are the row keys and the values are maps:
'usr1': {'password':'foo', 'thin
While we are talking same user names, it’s the application design to help
figuring out the difference on other attributes (actually, it’s not Cassandra
related, it’s application/ domain issue):
Let’s say there are two scenarios (let me know if there are more):
1. The identity behind t
How to handle same usernames. Otherwise seems fine to me.
On Sun, Apr 11, 2010 at 6:17 PM, Dop Sun wrote:
> Hi,
>
>
>
> As far as I can see it, the Cassandra API currently supports criterias on:
>
> Token – Key – Super Column Name (if applicable) - Column Names
>
>
>
> I guess Token is not usua
Hi,
As far as I can see it, the Cassandra API currently supports criterias on:
Token – Key – Super Column Name (if applicable) - Column Names
I guess Token is not usually used for the day to day queries, so, Key and
Column Names are normally used for querying. For the user name and passwo
It was just an example to showcase how i want to implement it, and I have
even added that this entierly depends upon what you want and what the
scenario is, i'm thinking of using this for articles that we are storing,
and the number is big. thinking of making each values as column name itself.
Onc
Can we not implement counts by just storing all the deltas in a row, and
then summing them all up to acheive a count.
If a row ends up with too many deltas, a reader could just summarise the
deltas occasionally into a single value (in a way which avoids race
conditions, of course).
So you'd map
On 11 April 2010 07:59, Lucifer Dignified wrote:
> For a very simple query wherin we need to check username and password I
> think keeping incremental numeric id as key and keeping the name and value
> same in the column family should work.
>
It is highly unlikely that your application has enou
Hi Benjamin
I'll try to make it more clear to you.
We have a user table with fields 'id', 'username', and 'password'. Now if
use the ideal way to store key/value, like :
username : vineetdaniel
timestamp
password :
timestamp
second user :
username:
timestamp
password:
and so on, here what i a
Sorry, I don't understand your example.
On Sun, Apr 11, 2010 at 12:54 AM, Lucifer Dignified
wrote:
> Benjamin I quite agree to you, but what in case of duplicate usernames,
> suppose if I am not using unique names as in email id's . If we have
> duplicacy in usernames we cannot use it for key, so
Dop
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On Sat, Apr 10, 2010 at 8:19
Hi
I've been thinking of using cassandra for our existing application, which
has a very complex RDBMS schema as of now, and we need to make a lot of
queries using joins and where.
Whereas we can eliminate joins by using duplicate entries, its still hard to
query cassandra. I have thought of a way
Benjamin I quite agree to you, but what in case of duplicate usernames,
suppose if I am not using unique names as in email id's . If we have
duplicacy in usernames we cannot use it for key, so what should be the
solution. I think keeping incremental numeric id as key and keeping the name
and value
You would have a Column Family, not a column for that; let's call it
the Users CF. You'd use username as the row key and have a column
called 'password'. For your example query, you'd retrieve row key
'usr2', column 'password'. The general pattern is that you create CFs
to act as indices for eac
What will be the latency for the zk based atomic increase?
On Tue, Apr 6, 2010 at 8:22 PM, Chris Goffinet wrote:
> http://issues.apache.org/jira/browse/CASSANDRA-704
> http://issues.apache.org/jira/browse/CASSANDRA-721
> We have our own internal codebase of Cassandra at Digg. But we are using
> t
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